Robert L Goldenberg, William W Andrews, Brian M Mercer et al (Dept. of Obstetrics and Gynecology, Birmingham, Alabama, Cincinnati and Columbus etc.)
The Preterm Prediction Study: Granulocyte colony-stimulating factor and spontaneous preterm birth.
Am J Obstet & Gynecol, March 2000, 182: 625-30.
Granulocyte colony-stimulating factor is elevated in the amniotic fluid and plasma of women with chorioamnionitis and active preterm labor. The authors investigated the relationship between plasma granulocyte colony stimulating factor and subsequent spontaneous preterm birth in pregnant women without symptoms.
Study Design : The authors performed a nested case-control study involving 194 women who had a singleton spontaneous preterm birth and 194 matched term control subjects from the patient pool enrolled in the Preterm Prediction Study. Plasma collected at 24 and 28 weeks gestation was analysed for granulocyte colony stimulating factor, and the results were compared with subsequent spontaneous preterm birth.
Conclusion: In pregnant women without symptoms at 24 and 28 weeks gestation, elevated plasma granulocyte colony-stimulating factor levels are associated with subsequent early (<32 weeks gestation) spontaneous preterm birth, especially within the next 4 weeks, but not with late spontaneous preterm birth. These data provide further evidence that early spontaneous preterm birth is associated with an inflammatory process that is identifiable by the presence of a cytokine in maternal plasma several weeks before the early spontaneous preterm birth; however, later spontaneous preterm birth is not associated with this process.
Robert L Goldenberg, W.W.Andrews et al (Dept. of Obstetrics and Gynecology, Birmingham, Alabama, Charlottesville, etc.)
The Preterm Prediction Study: Cervical lactoferrin concentration, other markers of lower genital tract infection, and preterm birth.
Am J Obstet &Gynecol, March 2000, 182: 631-5.
This study was undertaken to determine the relationship among cervical lactoferrin concentration, other cervical markers potentially related to infection, and spontaneous preterm birth.
They concluded that lactoferrin found in the cervix correlated well with other markers of lower genital tract infection. High lactoferrin levels were associated with spontaneous preterm birth but had a very low predictive sensitivity.
Comment: To date, it is quite clear that both bacterial vaginosis and cervical or vaginal fetal fibronectin detection are both associated with clinically silent upper genital tract infection.
These results raise the question as to the origin of the lactoferrin found in the cervix. Lactoferrin a white blood cell product, either may originate in the upper genital tract and seep into the cervix, as does fetal fibronectin, or may be a product of local lower genital tract white blood cells present as part of the inflammatory process associated with bacterial vaginosis. That the relationship of cervical lactoferrin with bacterial vaginosis and activity of sialidase, a bacterial vaginosis-related enzyme, appears stronger than that with fetal fibronectin suggests that cervical lactoferrin concentrations may reflect lower genital tract infection better than upper genital tract infection. This, in turn, may explain the low sensitivity of cervical lactoferrin levels in predicting spontaneous preterm birth and te observation that only extremely high cervical lactoferrin levels were associated with preterm birth. The relatively low cervical levels of lactoferrin found in this study, as opposed to the higher concentrations found in previous studies of vaginal fluid may have been caused by differences in assay technique or, more likely, arose because the origins of the fluids were different.
Achieving a better understanding of the relationships among the various organisms present in the lower and upper genital tract, substances secreted by these organisms, and the host response -including various immunoglobulins, cytokines, and now lactoferrin – is crucial if they were to achieve reductions in infection -related preterm birth and the associated maternal neonatal morbidity.
Robert L Goldenberg, Jay D. Iams, Anita Das, et al (Dept. of Obstetrics & Gynecology, Univ. of Alabama, Birmingham, Columbus, Cincinnati, Ohio etc.)
The Preterm Prediction Study: Sequential cervical length and fetal fibronectin testing for the prediction of spontaneous preterm birth.
Am J Obstet & Gynecol, March 2000, 182(3), 636-43.
The authors concluded that regardless of other risk factors, a short cervix predicts a subsequent positive fetal fibronectin result, and a positive fetal fibronectin result predicts subsequent cervical shortening. These data do not support a single sequence of events leading to spontaneous preterm birth.
Comments: Certainly, these data indicate that both a short cervix and a positive fetal fibronectin result, either separately or (especially) together, are potent predictors of subsequent preterm birth and that both are more often present among women with other risk factors. Furthermore, physician or patient awareness of increased risk of preterm birth has generally not led to effective prevention of preterm birth. Therefore the proof of clinical usefulness of these predictors of preterm birth, potent as they are, awaits the results of interventional trials that use these markers to identify the population at risk. Until then, the clinical utility of these tests remains unknown, and no firm recommendations about how to use them can be made.
Mikiya Nakatsuka, Toshihiro Habara, et al (Dept of Obstetrics and Gynecology, Okayama, Univ Medical School)
Elevation of total nitrite and nitrate concentration in vaginal secretions as a predictor of premature delivery.
Am J Obstet Gynecol, March 2000, 182: 644-45.
Comment: These results suggest that the elevation of total nitrite and nitrate concentration in vaginal secretion is accompanied by premature rupture of membranes and that it precedes premature delivery. Although the source of the nitrite and nitrate in vaginal secretions was not fully determined, infiltrating inflammatory cells and constitutive cells in the vagina or uterine cervix may produce a large amount of nitric oxide by stimulation with lipopolysaccharide and inflammatory cytokines. Because nitric oxide has been known to activate matrix metalloproteinases and induce apoptotic cell death in various cells, overproduction of nitric oxide not only may be a predictive marker but may also be involved in cervical ripening, fragility of membranes, and subsequent premature delivery. Their results support this hypothesis. Washing out and disinfection of the vagina of a patient with local infection thus may be effective in prevention of premature delivery. Furthermore, suppressors of nitric oxide synthesis may be candidate therapeutic agents.
Bernard Gonik, Alberta Walker and Michele Grimm (Detroit, Michigan)
Mathematic modeling of forces associated with shoulder dystocia: A comparison of endogenous and exogenous sources.
Am J Obstet Gynecol, March 2000; 182: 689-91
Objective: A mathematic model was developed to estimate the compressive pressure on the fetal neck overlying the roots of the brachial plexus by the symphysis pubis during a shoulder dystocia event. The induced pressure was calculated for both exogenous (clinician applied) and endogenous (maternal and uterine) forces during the second stage of labor.
Study Design: Intrauterine pressure and clinician applied force data were taken from the existing literature. A free-body diagram was generated and equilibrium equations were used to calculate the contact pressure between the base of the fetal neck and the symphysis pubis during a shoulder dystocia event.
Results: Clinician applied traction to the fetal head (exogenous force) led to an estimated contact pressure of 22.9kPa between the fetal neck and the symphysis pubis. In contrast, uterine and maternal expulsive efforts (endogenous forces) resulted in contact pressures that ranged from 91.1 to 202.5kPa. The estimated pressures resulting from endogenous forces are 4 to 9 times greater than the value calculated for clinician applied forces.
Conclusion: Neonatal brachial plexus injury is not a priori explained by iatrogenically induced excessive traction. Spontaneous endogenous forces may contribute substantially to this type of neonatal trauma.
Larry C Matsumoto, Cecilia Y Cheung, and Robert A Brace (San Diego, California)
Effect of esophageal ligation on amniotic fluid volume and urinary flow rate in fetal sheep.
Am J Obstet Gynecol, March 2000; 182: 699-705.
Objective : Although the fetus normally swallows large volumes of amniotic fluid each day, it is unclear whether amniotic fluid volume increases after fetal esophageal obstruction or whether fetal urine production changes. Our objective was to determine the effects of fetal esophageal ligation on amniotic fluid volume and urinary flow rate over time.
Study Design: Seven late-gestation fetal sheep underwent esophageal ligation, and 7 served as time control animals. The urachus was ligated to eliminate urine flow to the allantoic cavity. On days 1,3,5,7 and 9 after surgery, the authors measured the composition of amniotic fluid, fetal urine, and fetal and maternal blood, as well as amniotic fluid volume and fetal urinary flow rate. A 3-factor analysis of variance was used for statistical analysis.
Results: Amniotic fluid volume did not change with time in the control group, averaging 876 ± 142 mL (mean ± SEM), and it decreased in the esophageal ligation group (P =0.20), averaging 309 ± 75 mL on day 9. Fetal urinary flow rate was lower (P =.0063) in the esophageal ligation group (431 ± 27 nL/d) than in the control group (631 ± 54 mL/d). There were no differences in fetal or maternal blood compositions between the two groups. Amniotic fluid sodium and chloride increased in the ligated animals.
Conclusion: Polyhydramnios did not occur after esophageal ligation, even though the fetuses excreted approximately 4000 mL of urine over the 9-day study period. This suggests that intramembranous absorption is substantially increased. With only small changes in amniotic solute concentrations, intramembranous solute absorption must occur simultaneously with water, suggesting a near-zero reflection coefficient for solutes. The authors speculate that fetal urine, lung secretions, or both contain a factor that increases intramembranous permeability.
Jan E Dickinson and Sharon F Evans, for the Australian and New Zealand Twin- Twin Transfusion Registry Group.
Obstetric and perinatal outcomes from The Australian and New Zealand Twin-Twin Transfusion Syndrome Registry.
Am J Obstet Gynecol, March 2000; 182: 706-12
Objective: Authors purpose was to investigate the antepartum characteristics and perinatal outcomes of twin-twin transfusion syndrome cases from a multicenter national registry.
Results: One hundred twelve cases of twin-twin transfusion syndrome were registered. The median gestation at diagnosis was 21.5 weeks (range, 14.4-34.6 weeks). Oligohydramnios-polyhydramnios sequence was the most common presentation, with 84% of cases invovling “stuck” twinning. Therapeutic amnioreduction was used in 92 cases (82.1%) with the median number of procedures per case being 2 (range, 1-23), the median gestation at delivery was 29 weeks (range, 18-38 weeks). The overall perinatal survival rate was 62.5%. Abnormal findings on cranial ultrasonography were present in 27.3% of live neonates, and periventricular leukomalacia was reported in 10.8%. Increased gestational age at delivery, the presence of umbilical artery diastolic flow, and a prolonged interval from final amnioreduction to delivery were positively associated with the delivery of live fetuses without complications.
Conclusion: The majority of antenatally identified cases of twin-twin transfusion syndrome are managed with serial amnioreduction. Despite contemporary obstetric and neonatal management strategies, perinatal mortality and morbidity rates are high.
Shantala H Vadeyar, Rachel J Moore, et al (Nottingham, United Kingdom)
Effect of fetal magnetic resonance imaging on fetal heart rate patterns.
Am J Obstet Gynecol 2000; 182-666-9
Objective : Our aim was to record the fetal heart rate before and during magnetic resonance imaging to observe the effects of the magnetic resonance imaging process on fetal heart rate parameters during imaging.
Study Design: Fetal heart rate recordings were obtained in 10 pregnant volunteers at the time of magnetic resonance imaging. All the pregnant women were at term (37-41 weeks) with singleton fetuses in the cephalic presentation. The scanning was performed on a 0.5-T purpose-built superconductive magnet by use of echo-planar imaging. The fetal heart recordings were obtained with a modified Sonicaid Meridian 800 (Oxford) Doppler ultrasound monitor. Recordings of the fetal heart were made for a period of at least 15 minutes outside the magnet and then for at least 15 minutes inside the magnet.
Conclusion: This is the first report of fetal heart rate recording during magnetic resonance imaging of the fetus. Magnetic resonance imaging does not produce demonstrable effects on fetal heart rate patterns.
Bo Hyun Yoon, Roberto Romero, et al (Seoul, Korea)
Fetal exposure to an intra-amniotic inflammation and the development of cerebral palsy at the age of three years.
Am J Obstet Gynecol March 2000, 182: 675-81.
Objective : Cerebral palsy is a symptom complex characterized by the aberrant control of movement or posture that appears in early life and can lead to costly life-long disability. Cerebral palsy has been traditionally linked to hypoxic obstetric events occurring during the antepartum and intrapartum periods. However, several studies have demonstrated a limited role for birth asphyxia in the etiology of cerebral palsy, and most cases remain unexplained. A growing body of recent epidemiologic, clinical, and experimental evidence provides strong support for a role of intrauterine infection or inflammation in the etiology of this disorder.
Premature birth, the leading identifiable cause of cerebral palsy, has been associated with subclinical intrauterine infection, which is thought to be present in ³ 25% of all patients who deliver preterm. Proinflammatory cytokines have been implicated in the mechanism responsible for both the initiation of preterm parturition and the brain lesions associated with cerebral palsy. The purpose of this study was to determine whether fetal exposure to intra-amniotic inflammation, as determined by elevated amniotic fluid concentrations of proinflammatory cytokines, and evidence of a systemic fetal inflammatory response, as reflected by funisitis, are associated with the development of cerebral palsy at the age of 3 years.
Study Design : This cohort study included 123 preterm singleton newborns (gestational age at birth, £35 weeks) born to mothers who underwent amniocentesis and were followed up for ³3 years. The presence of intra-amniotic inflammation was determined by elevated amniotic fluid concentrations of proinflammatory cytokines such as interleukins 6 and 8 and by amniotic fluid white blood cell count. Cytokine concentrations were mesured with sensitive and specific immunoassays. Funisitis was diagnosed in the presence of neutrophil infiltration into the umbilical vessel walls or Wharton jelly. Cerebral palsy was diagnosed by neurologic examination at the age of 3 years.
Results : Newborns with subsequent development of cerebral palsy had a higher rate of funisitis and were born to mothers with higher median concentrations of interleukins 6 and 8 and higher white blood cell counts in the amniotic fluid compared with newborns without subsequent development of cerebral palsy (funisitis:75% vs 23%; interleukin 6: median, 18.9 ng/mL; range, 0.02-92.5 ng/mL; vs median, 1.2 ng/mL; range 0.01-115.2 ng/mL; interleukin 8: median, 13.0 ng/mL; range, 0.1-294.5 ng/mL; vs median, 1.2ng/mL; range, 0.05-285.0 ng/mL; white blood cell count: median, 198 cells/mm3, range, 0-> 1000 cells/mm3; vs median, 3 cells/mm3; range, 0-19, 764 cells/mm3; P<.01 for each). After adjustment for the gestational age at birth, the presence of funisitis and elevated concentrations of interluekins 6 and 8 in amniotic fluid significantly increased the odds of development of cerebral palsy (funisitis: odds ratio, 5.5; 95% confidence interval, 1.2-24.5; interleukin 6: odds ratio, 6.4; 95% confidence interval, 1.3-33.0; interleukin 8: odds ratio, 5.9; 95% confidence interval, 1.1-30.7; P<.05 for each).
Conclusion: This study provides evidence that the injury responsible for the neurologic damage leading to cerebral palsy begins in utero and is related to exposure to intra-amniotic inflammation and the development of a fetal systemic inflammatory response. Strategies to prevent cerebral palsy in this population of patients may need to begin in utero.
Comment: Cerebral palsy can be considered as a complex multifactorial syndrome determined by the interaction of environmental and genetic factors. One of the environmental factors is exposure to infection while the genotype determines the intensity of the inflammatory response.
A Randomized Trial on the Use of Ultrasonogrpahy or Office Hysteroscopy for Endometrial Assessment in Postmenopausal Patients with Breast Cancer who were Treated with Tamoxifen.
D Timmerman, J Deprest, et al (Univ Hosp. Leuven, Belgium)
Am J Obstet Gynecol 179:62-70, 1998.
The mortality rate in women with breast cancer has been reduced by tamoxifen and this drug is currently the hormonal treatment of choice. About 1 million women are taking tamoxifen in the United States currently. There is now an increased interest in the potential side effects of tamoxifen, particularly because it is used as a prophylactic agent against breast cancer.
There were 53 postmenopausal women with breast cancer who had no vaginal bleeding and who had taken tamoxifen at 20 or 40 mg/day for at least 6 months.
Results – Endometrial cancer was found in 2 women. In both patients, endometrial cancer was detected only by transvaginal. One woman had primary and other had breast secondary. At least 1 polyp was found in 26 women. All 47 polyps were benign. There was no significant difference among the women who had polyps with regard to their age, body mass, months of tamoxifen intake, or their cumulative dose. The sensitivity of transvaginal ultrasound was 90% and the specificity was 100%. For office hysteroscopy, the sensitivity was 77% and the specificity was 92%.
Some patients could not have office hysteroscopy due to cervical stenosis i.e. 19% of patients in the study.
Hwa Sook Moon, Young Joo Choi et al (Department of Obstetrics and Gynecology, Centre for Reproductive Medicine and Laparoscopic Surgery, Moon Hwa Hospital)
New Simple Endoscopic Operations for Interstitial Pregnancies
Am J Obstet Gynaecol, 182(1) Part 1, p.114-121
Interstitial or cornual pregnancy is a rare form of ectopic pregnancy. In previous reports it accounted for 2% to 4% of all ectopic pregnancies, and it occurs once in every 2500 to 5000 live births. There is a 2% to 5% mortality rate. In general, interstitial pregnancies are diagnosed later in gestation, and if rupture occurs, hemorrhage is profound. Traditional treatment has consisted of cornual resection or hysterectomy by laparotomy. Methods of diagnosis and treatment have posed difficulties; however, the development of ultrasonography and serum human chorionic gonadotropin (hCG) measurement have allowed earlier diagnosis. Furthermore, endoscopic technology and methotrexate have allowed minimally invasive treatment. Many successful endoscopic managements for early interstitial pregnancy have been reported by several authors. In the previous reports most authors used the electric cauterization method for bleeding control and cornual incision. Some authors have performed cornual excision. Some applied multiple procedures for hemostasis.
For the successful management of interstitial pregnancy, we expect minimal blood loss during the operation, an observed decrease in the serum hCG level, and early resumption of menstruation after operation. The outcome of subsequent pregnancy is very important for women who want future pregnancy. Patients with interstitial pregnancies who have been treated conservatively may have a risk of uterine rupture in subsequent pregnancies; however, limited information is available.
This study was performed retrospectively to provide information on the endoscopic management of interstitial pregnancy, to introduce simple and safe surgical techniques, and to report the outcomes of subsequent pregnancies.
Study Design :This is an uncontrolled retrospective review of 24 patients treated for interstitial pregnancies through endoscopic operations with 14 to 72 months of follow-up at a large urban medical center. Blood loss, operation time, changes of serum human chorionic gonadotropin levels, the resumption of menstruation, and subsequent pregnancy after operation were analyzed.
Results : Among 24 interstitial pregnancies, 3 had ruptured at the time of operation and 21 had not ruptured. Treatment consisted of either the vasopressin and electric cauterization method, the endoloop before evacuation of the conceptus method, or the encircling suture before evacuation of the conceptus method. The blood loss and operation time (mean ± SD) for unruptured cases were 133 ± 134 mL and 51.6 ± 7.6 minutes in the vasopressin and electric cauterization group (n=3), 32 ± 22mL and 28.5 ± 6.4 minutes in the endoloop group (n=15), and 40 ± 17mL and 35.0 ± 5.0 minutes in the encircling suture group (n=3). In 3 patients with ruptured pregnancy treated with the endoloop method, the blood loss and operation time (mean ± SD) were 1100 ± 854 mL and 82.5 ± 51.6 minutes. Any of these operative methods resulted in rapid decline of serum human chorionic gonadotropin levels within 1 week with the exception of 1 case, in which the endoloop method was used; this patient needed additional treatment with methotrexate. Seventeen patients desired pregnancy in the future, and 15 eventually became pregnant. One of these 15 pregnancies ended in an ectopic pregnancy on the opposite side 6 months after the interstitial pregnancy. Three ended in a spontaneous abortion and 11 were delivered by elective cesarean section at term before labor started. Operative records of cesarean section in 8 patients delivered at our institution showed little or no adhesions or defect in the cornual area of the previous operation.
Conclusion: the endoloop method and the encircling suture method are simple, safe, effective and nearly bloodless. There were no uterine ruptures in the pregnancies subsequent to these methods of endoscopic management.
Ahmet A Baschat and Carl P Weiner, (Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland).
Umbilical artery Doppler screening for detection of the small fetus in need of antepartum surveillance.
Am J Obstet Gynecol 182(1), Part I, p. 154-8.
Detection of fetal hypoxemia is the prime goal of antenatal surveillance, and intrauterine fetal growth restriction (IUGR) is among the most common risk factors for chronic fetal hypoxemia. Fetuses measured as being small for gestational age on ultrasonography are routinely evaluated with weekly nonstress tests or biophysical profiles specifically in search of evidence of hypoxic fetal distress. Yet the positive predictive value of ultrasonographic biometry for diagnosis of IUGR approximates only 50%. Thus half of the ultrasonographically small fetuses are not truly at risk, and their selection for testing dramatically increases the cost of health care.
Knowledge of increased umbilical artery (UA) Doppler – determined resistance is associated with a reduction in perinatal morbidity and mortality when applied to populations at high risk for an adverse perinatal outcome. Relatively unexplored is the use of Doppler to select fetuses who might benefit from weekly surveillance because their ultransonographic biometric results suggest IUGR. The purpose of this study was to determine whether an abnormal UA resistance both improves the diagnostic accuracy of IUGR and identifies the fetus who is at risk for chronic hypoxemic distress and thus in need of antenatal surveillance. If true, this application of Doppler velocimetry would reduce the total population in need of weekly antenatal testing by improving specificity and thus lower the cost of antenatal chart without sacrificing outcome.
Study Design: Three hundred eight fetuses with either an ultrasonographic weight estimate < 10th percentile for gestational age or an abdominal circumference <2.5th percentile for gestational age or both of these had an umbilical artery Doppler measurement of the systolic/diastolic ratio. A systolic/diastolic ratio >90th percentile for gestation was considered abnormal. The incidences of a birth weight < 10th percentile, fetal distress, and metabolic acidemia were recorded fore both groups (normal vs abnormal umbilical artery Doppler).
Results : Only the umbilical artery systolic/diastolic ratio predicted perinatal outcome in the group of fetuses who were presumed to be small for gestational age. Those 138 fetuses with elevated umbilical artery systolic/diastolic ratios had lower umbilical artery and vein pH values at birth (artery, 7.23 ± 0.08 vs 7.25 ± 0.1; P<.02; vein, 7.31 ± 0.01 vs. 7.34 ± 0.09; P =.01), an increased likelihood of fetal distress consistent with chronic hypoxemia (26.3% vs 8.6%; P<.0001), more admissions to the neonatal intensive care unit (40.7% vs 30.7%; P < .005), and a higher incidence of respiratory distress (66% vs 27.3%; P < .03).
However, it is important that no fetus with a normal Doppler flow measurement was delivered with a metabolic acidemia associated with chronic hypoxemia. Further, the likelihood of a false-positive diagnosis of intrauterine growth restriction was increased in the group with a normal umbilical artery Doppler resistance.
Conclusion: Antenatal surveillance may be unnecessary in fetuses with suspected intrauterine growth restriction if the umbilical artery systolic/diastolic ratio and amniotic fluid volume are normal, because the complications that occur are intrapartum. If these findings are confirmed in prospective trials, the cost implication of reducing the number of antenatal surveillance tests administered I this group of patients is great.
Robert L Goldenberg, Anita Das, for the National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network, Birmingham, Alabama and Washington.
Fetal Fibronectin and bacterial vaginosis in smokers and nonsmokers.
Am J Obstet Gynecol 2000; 182: 164-6.
The National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network previously reported that there was a statistically significant association between the detection of fetal fibronectin and the presence of bacterial vaginosis. This relationship was subsequently confirmed but with the added observation that the relationship was statistically significant only among women who smoked during pregnancy. If this latter observation is indeed true and bacterial vaginosis predicts elevated fetal fibronectin levels only among women who smoke, this could suggest how 2 different risk factors for preterm birth might interact with each other.
To determine whether maternal smoking influences the relationship between bacterial vaginosis and fetal fibronectin, the presence of cervical or vaginal fetal fibronectin, the presence of bacterial vaginosis and smoking status were determined for 2899 women at 24 weeks’ gestation. Fetal fibronectin was more common among women with bacterial vaginosis, but maternal smoking did not increase the likelihood that women with bacterial vaginosis would have fetal fibronectin detected. A previously reported impact of maternal smoking status on the relationship between bacterial vaginosis and fetal fibronectin thus was not confirmed.
Anna Locatelli, Maria Giovanna Piccoli, et al (Divisione di Ostetricia e Ginecologia, Istitutio di scienze Biomediche San Gerardo, and the Departments of Obstetrics and Gynecology and Pharmacology and Biostatistics, Georgetown University Medical Center.
Critical appraisal of the use of nuchal fold thickness measurements for the prediction of Down Syndrome.
Am J Obstet Gynecol 2000; 182: 192-7
Maternal serum analyte levels have been used successfully to adjust the maternal age-associated probability of fetal trisomy 21 throughout the reproductive years. Ultrasonography offers another noninvasive means of selecting candidates for prenatal diagnosis of Down syndrome by using markers that are more frequently present in aneuploid fetuses than in euploid fetuses. Among the second-trimester ultrasonographic markers proposed, nuchal fold thickness has been consistently shown to be reproducible, to be easy to obtain, and to have a predictive ability that is independent of the other markers. A nuchal fold thickness ³6mm during the early second trimester has been reported to be the best ultrasonographic predictor of fetal chromosomal abnormalities and of trisomy 21 in particular. However, nuchal fold thickness has been shown to be correlated with gestational age. Therefore use of a single threshold across the early second trimester may not optimize the predictive ability of this marker. In addition, use of a single threshold of nuchal fold thickness independently from the prior probability (e.g. maternal age ) does not allow adjustment of the sensitivity and the false-positive rate according to the individual patient’s risk-level.
To obviate the confounding effect of gestational age on nuchal fold thickness and to allow calculation of posterior probabilities of Down syndrome on the basis of individual previously assessed risk, the authors analyzed a cohort sample of women undergoing a second trimester genetic sonogram. They then used the differences between the observed and expected nuchal fold thickness at each gestational age to calculate likelihood ratios.
Study Design: Nuchal fold thickness was measured at ultrasonographic examination at 14 to 22 weeks’ gestation without previous knowledge of the fetal karyotype. Nuchal cystic hygromas were excluded from anal4sis. Statistical analyses included correlation, logistic regression to control for other ultrasonographic predictors of trisomy 21 and for maternal age, receiver operating characteristic curve, and likelihood ratios. P< .05 was considered significant.
Results : Mean gestational age at ultrasonography was 16.9 weeks gestation (range 14-22 weeks’ gestation0. Mean (±SD) nuchal fold thickness in fetuses with trisomy 21 (4.7 ± 1.6mm; n=29) was greater than in euploid fetuses (3.2 ± 0.9; n-780; p <.001). Logistic regression analysis established that nuchal fold thickness was a signficant predictor of trisomy 21 independent botyh of the other ultrasonographic markers and of maternal age (P< .001). Regression analysis showed that nuchal fold thickness was significantly correlated with gestational age among both fetuses with trisomy 21 and euploid fetuses and that the regression line of fetuses with trisomy 21 had a slope similar to that of euploid fetuses. The difference between observed and expected nuchal fold thicknesses on the basis of th ebiparietal diameter (as a function of gestational age) was used to obviate the confounding effect of gestational age. Differences between observed and expected nuchal fold thicknesses were then used to calculate likelihood ratios. These likelihood ratios could then be multiplied by the individual prior probability to obtain a patient – specific Down syndrome probability.
Conclusion: Nuchal fold thickness is correlated with gestational age in both euploid fetuses and fetuses with Down syndrome. Use of the difference between observed and expected nuchal fold thicknesses to determine likelihood ratios allows the calculation of individual posterior probabilities of Down syndrome that take into consideration both gestational age and maternal age.
Anthony M Vintzileous, Cande V Ananth et al (Piscataway, New Jersey and farmington, Connecticut)
Routine second-trimester ultrasonography in the United States: A Cost benefit analysis.
Am J Obstet Gynecol, March 2000, 182: 655-60.
Objective: The objective of this study was to perform a cost-benefit analysis of routine second-trimester screening ultrasonography in the United States as compared with performing ultrasonography only in the presence of indications.
Study Design: It was assumed that 1 million pregnant women are available annually who otherwise would not have an indication for an ultrasonographic examination. Cost savings from early detection and therapeutic abortion were considered only for fetal conditions for which lifetime cost estimates are available, including spina bifida, major cardiac disease, cleft lip or palate, renal agenesis or dysgenesis, urinary obstruction, lower or upper limb reduction, omphalocele, gastroschisis, and diaphragmatic hernia. Two separate cost-benefit analyses were considered with the range of fetal anomaly detection rates before 24 weeks’ gestation as reported by tertiary and non-tertiary centers in the Routine Antenatal Diagnostic Imaging with Ultrasound (RADIUS) trial. Potential cost savings from averting treatment for preterm labor and postdate gestations were also considered.
Results: The ratio of savings to cost was between 1.35 and 1.70 (savings of $1.35 – $1.70 per $1 spent) if the ultrasonographic examinations were performed in tertiary care centers. The ratio of savings to cost was between 0.40 and 0.74 (loss of $0.26-$0.60 per $1 spent) if the examinations were performed in nontertiary centers. If the screening ultrasonography was performed in tertiary centers, the expected annual net benefits were estimated $97 to 189 million. If ultrasonographic screening was performed in nontertiary centers, the expected annual net losses were estimated at $69 to 161 million.
Conclusion: Routine second-trimester ultrasonographic screening appears to be associated with net benefits only if the ultrasonography is performed in tertiary care centers.
Mathematic modeling of forces associated with shoulder dystocia: A comparison of endogenous and exogenous sources.
Am J Obstet Gynecol, March 2000; 182: 689-91
Objective: A mathematic model was developed to estimate the compressive pressure on the fetal neck overlying the roots of the brachial plexus by the symphysis pubis during a shoulder dystocia event. The induced pressure was calculated for both exogenous (clinician applied) and endogenous (maternal and uterine) forces during the second stage of labor.
Study Design: Intrauterine pressure and clinician applied force data were taken from the existing literature. A free-body diagram was generated and equilibrium equations were used to calculate the contact pressure between the base of the fetal neck and the symphysis pubis during a shoulder dystocia event.
Results: Clinician applied traction to the fetal head (exogenous force) led to an estimated contact pressure of 22.9kPa between the fetal neck and the symphysis pubis. In contrast, uterine and maternal expulsive efforts (endogenous forces) resulted in contact pressures that ranged from 91.1 to 202.5kPa. The estimated pressures resulting from endogenous forces are 4 to 9 times greater than the value calculated for clinician applied forces.
Conclusion: Neonatal brachial plexus injury is not a priori explained by iatrogenically induced excessive traction. Spontaneous endogenous forces may contribute substantially to this type of neonatal trauma.
Rodien P, Bremont C, Sanson M-LR, et al [Universite Libre de Bruxelles, Brussels, Belgium; Hopital Cochin, Paris; Centre National pour Ia Recherche Scientifique, Paris]
Familial Gestational Hypethyroidism Caused by a Mutant Thyrotropin Receptor Hypersensitive to Human Chorionic Gonadotropin.
N Engl J Med 339: 1823-1826, 1998
Because of the structural similarity of chorionic gonadotropin and thyrotropin, some stimulation of the thyroid gland by human chorionic gonadotropin [hCG] is common in early pregnancy. Hyperemesis gravidarum is characterized by excessive vomiting in ealy pregancy. Some women with this condition have high serum thyroid hormone concentrations, and some have high serum chorionic gonadotropin concentrations. This case report described a woman with recurrent gestational hyperthyroidism and normal serum chorionic gonadotropin concentrations, who was heterozygous for a mutation in the thyrotropin receptor, rendering it hypersensitive to chorionic gonadotropin. The womans mother also carried this mutation.
The gestational hyperthyroidism described in the women reported in this article has a different mechanism than that associated with molar pregnancies and at least in some women with hyperemesis gravidarum. In the latter two conditions, hyperthryroidism results from activation of the thyrotropin receptor by excessive quantities of normal chorionic gonadotropin or by chorionic gonadotropin molecules with increased thyrotropin like activity. Both conditions are thought to represent an exaggeration of normal thyroid stimulation caused by maximal chorionic gonadotropin production that occurs early in pregnancy in many normal women.
Fergal D Malone, Richard L Berkowitz, et al Department of Obstetrics and Gynaecology, Columbia.
First-trimester screening for aneuploidy : Research or standard of care ?
Am J Obstet Gynecol, March 2000, 182: 490-6)
First-trimester screening for Down syndrome has been proposed as a significant improvement with respect to second-trimester serum screening programs, the current standard of care, because of apparently higher detection rates and an earlier gestational age at diagnosis. First-trimester nuchal translucency on ultrasonography forms the basis of this new form of screening, although studies of its efficacy have yielded widely conflicting results, with detection rates ranging from 29% to 91%. Studies of first-trimester serum screening with measurements of pregnancy-associated plasma protein A and free B-human chorionic gonadotropin serum concentrations have been much more consistent, with Down syndrome detection rates of 55% to 63% at a 5% false-positive rate. The combination of first-trimester ultrasonographic and serum screening has the potential to yield a Down syndrome detection rate of 80% at a 5% false-positive rate, although this approach has not been adequately studied. There have been no studies performed to date to directly compare the performance of first-trimester and second-trimester methods of screening.
Two major trials are underway that will address this issue, one in the United Kingdom and one in United States. Until the results of these trials are available, the current standard of care with respect to Down syndrome screening should not be changed, and first-trimester screening should remain investigational.
Intrauterine mortality rates of aneuploid fetuses:
It is inappropriate to compare the detection rate for Down syndrome derived from first-trimester intervention studies with previous reports describing detection rates for second-trimester serum screening. Such a comparision will always be biased in favor of first-trimester screening because of the higher prevalence of Down syndrome in the first-trimester and the expected miscarriage of fetuses with Down syndrome between the times of first and second trimester screening. The only way to accurately compare the Down syndrome detection rates between first and second trimester forms of screening is to perform a noninterventional trial in which all patients undergo both first and second trimester screening, at the completion of which the two approaches to screening can be objectively compared.
Benjamin Caspi, Roni Levi, et al ( Department of Obstetrics and Gynaecology, Tel Aviv, Israel )
Conservative Management of Ovarian Cystic Teratoma during Pregnancy and Labor.
Am J Obstet Gynaecol, March 2000; 182: 503-5
Authors had followed up with 49 women with ultrasonographically diagnosed ovarian cystic teratoma <6m for detection of possible complications through pregnancy and labor. Serial ultrasonographic examinations before pregnancy, during pregnancy, and after delivery were performed.
Conclusions: Ovarian dermoid cysts <6cm are not expected to grow during pregnancy or to cause complications in pregnancy and labor, such as torsion, dystocia or rupture on the adequacy of conservative management of success.
Perucchini d, Fischer U, et al (Univ Hosp Zurich, Switzerland)
Using Fasting Plasma Glucose Concentrations to Screen for Gestational Diabetes Mellitus: Prospective Population Based Study.
BMJ 319: 812-815, 1999
Identifying women who are susceptible to gestational diabetes can help prevent perinatal morbidity and improve long-term outcomes for the mother and baby. Whether measurement of fasting glucose concentration is easier than the 1 hour, 50-g glucose challenge test in the screening of gestational diabetes mellitus was investigated.
The measurement of FPG levels, with a cut-off value of 4.8 mmol/l or greater, is easier than the 50-g glucose challenge test in screening for gestational diabetes and obviates the need for the challenge test in 70% of women.
Editor’s comment: If confirmed in large studies, this will save doctors and patients very precious time. Longitudinal studies to examine the fetal and maternal outcomes of the use of FPG > 4.8 mmol/ml and 50-g glucose are needed.
Haddow JE, Palomaki GE, Allan WC, et al [ Found for Blood Research, Scarborough, ME; New England Newborn Screening Program, Jamaica Plain, Mass; Children’s Hosp, Boston; et al ]
Maternal Thyroid Deficiency During Pregnancy and Subsequent Neuropsychological Development of the Child
N Engl J Me d 341: 549-555, 1999
Purpose – Iodine deficiency in pregnant women causes thyroid deficiency for both the mother and fetus, leading to adverse neuropsychologic sequelae for the child. However, it is unclear whether the same developmental problems occur if only maternal hypothyroidism is present.
Methods – The study included stored serum samples from 25,216 pregnant women, collected over 3 years in which thyrotropin levels were measured. From these were identified 47 women with serum thyrotropin levels at or above the 99.7th percentile; 15 women with values from the 98th through 99.6th percentiles, along with low thyroxine levels; and a match sample of 124 women with normal values. A battery of neuropsychologic tests was performed on the women’s 7 to 9 year old offspring, all of whom were free of hypothyroidism as newborn infants. The battery included tests of intelligence, attention, language, reading, school performance, and visual-motor performance.
Conclusions – The findings suggest that adverse developmental effects may result from undiagnosed hypothyroidism during pregnancy, even in the absense of neonatal hypothyroidism. The results support the use of screening for thyroid deficiency in pregnant women. Testing should be performed at the first prenatal visit, with prompt follow-up for women who have positive screening results.
This study supports the notion that the mother is the sole source of thyroid hormones until about 12 weeks’ gestation, when the fetal gland becomes active. A smaller study published earlier in 1999 showed that children of women with low free throxine levels at 12 weeks’ gestation had impaired psychomotor development at 10 months of age. The need for thyroxine increases for many women with primary hypothyroidism when they are pregnant.
Steven G Gabbe, Emily Holing, et al (Seattle, Washington)
Benefits, risks, costs, and patient satisfaction associated with insulin pump therapy for the pregnancy complicated by type 1 diabetes mellitus.
Am J Obstet Gynecol, 182; 1283-91
Objective : Glycemic control, perinatal outcome, and health care costs were evaluated among women with type 1 diabetes mellitus who began insulin pump therapy during pregnancy (group 1, n =24), were treated with multiple insulin injections (group2, n=24), or were already using an insulin pump before pregnancy (group 3, n=12). Patient satisfaction and continuation of pump therapy post partum were assessed.
Study Design: A retrospective review of maternal and neonatal medical records was performed, and a questionnaire was sent to patients after delivery. Patients in groups 1 and 2 were matched for age, age at onset and duration of diabetes mellitus, white class and date of delivery.
Results : After delivery 94.7% of the women in group 1 continued to use the pump because it provided better glycemic control and a more flexible lifestyle.
Conclusions: Insulin pump therapy was initiated during pregnancy without a deterioration of glycemic control and was associated with maternal and perinatal outcomes and health care costs comparable to those among women who were already using the pump before pregnancy or who received multiple-dose insulin therapy. Women who began pump therapy in pregnancy were highly likely to continue pump use after delivery and preferred the flexible lifestyle that this treatment allowed.
Insulin pump therapy was developed by Dr. Arnold Kadish of Los Angeles. The insulin pump from its onset was ocassionally used for pregnant women, especially for those women who had particularly brittle diabetes. Insulin lispro decreases the frequency of hypoglycemia and hemoglobin A1c with respect to other forms of insulin.
The fetal malformation rate was 12.5% in both groups 1 and 2, reflecting the early fetal development during a time of hyperglycemia. In contrast, women who began pregnancy while already using the insulin pump and continued pump use did not have any fetal malformations in this study. Is this not enough evidence for us to encourage the use of the pump by all women of reproductive age who may be candidates?
American Diabetes Association recommends that patients with diabetes maintain a hemoglobin A1c concentration of 7% or a mean glucose concentration of about150mg dL, just what our patients who continued to use the pump after delivery were able to do.
Most of their patients take 3 or 4 injections per day, generally with neutral protamine Hagedorn insulin and regular insulin or insulin lispro.
Finally, Dr. Bradley asked when pump therapy should be started. It think that ideally you would like it to begin before pregnancy, so that you can avoid the risks during pregnancy, particularly of ketoacidosis should you have pump failure.
Maternal and Fetal Physiology
D M Main, E K Main, et al (San Francisco,California)
The relationship between maternal age and uterine dysfunction: A continuous effect throughout reproductive life.
Am J Obstet Gynecol 2000; 182:1312-20)
Objective : In a selected low-risk population with spontaneous term labour the authors sought to determine whether there was a continuous effect of maternal age on uterine function.
Study Design: The authors identified 8496 patients who were nulliparous and in spontaneous labor at term (³ 37 weeks’ gestation) with singleton fetuses in vertex presentation. This group was then analyzed according to maternal age for measures of labour dysfunction and rates of operative delivery. Analysis of variance and c2 statistics were used.
Conclusion : Among nulliparous patients with uncomplicated labour there is a continuously increasing risk of uterine dysfunction related to maternal age.
D P Reisner, M J Haas, et al ( Seattle, Washington)
Performance of a group B streptococcal prophylaxis protocol combining high-risk treatment and low-risk screening.
Am J Obstet & Gynecol, June 2000, pg.1335-43
Objective : This study was undertaken to evaluate a group B streptococcal protocol in a large community hospital that combined treatment of high-risk patients with rapid screening of low-risk patients.
Study Design: In a prospective cohort study from 1994 through 1996 laboring patients in a level III community hospital were considered to be at high risk for neonatal group B streptococcal transmission if they were at <37 weeks” gestation, if they had rupture of membranes > 12 hours, if they were known carriers of group B streptococci, if they had a temperature =100°F, if the gestation was complicated by fetal growth restriction or was a multiple gestation, or if they had a previous neonate infected with group B streptococci. High-risk patients were treated intravenously with antibiotics during labour. Low-risk patients were screened for group B streptococcal antigen by means of a rapid optical immunoassay. Patients with positive screening results were treated. Neonatal morbidity and mortality were evaluated.
Results : The maternal group B streptococcal carriage rate during the study was 18%. Group B streptococcal rapid optical immunoassay sensitivity was 81%. Elapsed time from screening to treatment was = 2½ hours for 93% of patients. No maternal anaphylaxis, no increase in bacterial neonatal sepsis caused by organisms other group B streptococci, and no protocol-related group B streptococcal antibiotic resistance were noted.
Conclusion: Successful implementation and maintenance of a protocol combining treatment of high-risk patients with rapid screening of low-risk patients during labour reduced neonatal group B streptococcal sepsis.
Comment: All high risk women should be treated during labour. Screening with antepartum cultures at 35 to 37 weeks’ gestation and screening with sensitive rapid intrapartum tests are both options for low-risk women.
Discussion: Dr. John A Enbom, Corvallis, Oregon. Before 1992 multiple studies established that group B ß-hemolytic streptococci are carried in the anorectal and vaginal flora of many women, easily 20% to 30%.
The American Academy of Pediatrics recommended in 1992 universal antepartum screening at 26 to 28 weeks’ gestation and antepartum treatment of patients with group B streptococcal bacteria as well as with preterm rupture of membranes.
C S Naylor, L Steele, et al
Cefotetan-induced hemolysis associated with antibiotic prophylaxis for cesarean delivery.
Am J Obstet Gynecol 2000; 182: 1427-8
The authors described 3 cases of antibiotic-induced hemolysis associated with cefotetan prophylaxis during cesarean delivery. Each of the 3 patients showed development of significant anemia with documented cefotetan-induced hemolysis. When postpartum anemia is associated with antibiotic use, immune hemolytic anemia should be considered and included in the differential diagnosis.
L M Burke, A T Davenport, et al (Winston-Salem, North Carolina)
Predictors of success after embryo transfer: Experience from a single provider.
Am J Obstet Gynecol April 2000: 182: 1001-4
Objective : Our goal was to examine the variables present at the time of embryo transfer and to determine their effects on the clinical pregnancy rate.
Study Design : All fresh and frozen embryo transfers during a 3-year period in a university-based in vitro fertilization program were examined. Female age, previous in vitro fertilization attempt, diagnosis, embryo number and quality, transfer technique, and presence of a clinical pregnancy were reduced for each couple. Logistic regression analyses were performed both univariately and multivariately to determine the association between a clinical pregnancy and the independent variables.
Results: All transfers during the study period were included in the analysis. The four primary diagnoses were pelvic or tubal disease, male factor infertility, unexplained infertility, and endometriosis. The 46 frozen embryo transfers had a clinical pregnancy rate similar to that among the 159 fresh embryo transfers and were therefore included in the analysis. One variable was found to significantly affect the outcome, the number of high-grade embryos placed. The presence of a previous failed embryo transfer tended to lower the success rate for future attempts; however, this result did not reach statistical significance. The catheter type and the transfer difficulty did not affect outcome.
Conclusion: The two most important variables for predicting a clinical pregnancy are a first-time transfer and the number of high-grade embryos placed. Neither the type of embryo transfer catheter used nor the diagnosis affected outcome. In this small sample difficult embryo transfers did not diminish the chance for a successful outcome.
Genetics and Teratology
CC Kocun, JT Harrigan, et al (Neptune and New Brunswick, New Jersey)
Changing trends in patient decisions concerning genetic amniocentesis
Am J Obstet Gynecol 2000; 182: 1018-20)
Objective: This study was undertaken to determine whether there was a change in patient decisions concerning genetic amniocentesis during the period 1995-1998
Study Design: All patients referred for genetic counseling because of advanced maternal age, abnormal serum triple-screen results, or ultrasonographic abnormalities between January and March 1995 and between January and March 1998 were evaluated through a retrospective chart review. Patient characteristics included age, race and gestational age. Group 1 consisted of patients from 1995. Group 2 consisted of patients from 1998. Data on patient decisions concerning amniocentesis before and after genetic counseling and ultrasonographic examination were compared in each group. Groups 1 and 2 were then comparedd with respect to decisions before and after genetic counseling and ultrasonographic evaluation.
Results: A total of 112 patients were studied. Group1 consisted of 53 patients and group 2 consisted of 59 patients. When the groups were compared, no differences in age, race, or gestational age were noted. In group1, before counseling, 18 of 53 patients desired genetic testing, compared with 44 of 53 after counseling (P = .02). In group 2, before counseling, 4 of 59 patients desired genetic testing, compared with 15 of 59 after counseling (P =.01). A significantly greater number of patients in group1 than in group2 desired genetic testing both before counseling (n =18/53 vs n =4/59; P =.01) and after counseling (n = 44/53 vs n=15/59; P=.01)
Conclusion: Fewer patients at risk for Down syndrome in 1998 than in 1995 desired amniocentesis both before and after genetic counseling and ultrasonographic examination.
Comment: This is probably the result of introduction of maternal serum markers screening.
J Mourad, J P Elliot and L Lisboa (Phoenix, Arizona)
Appendicitis in pregnancy: New information that contradicts long-held clinical beliefs.
Am J Obstet Gynecol 2000; 182: 1027-9
Objective: Our purpose was to elicit a better understanding of the presentation of acute appendicitis in pregnancy and to clarify diagnostic dilemmas reported in the literature.
Study Design: The authors retrospectively reviewed 66,993 consecutive deliveries from 1986 to 1995 by a computer program. Selected records were reviewed for gestational age; signs and symptoms at presentation; complications including preterm contractions, preterm labor, and appendiceal rupture; and histologic diagnosis of appendicitis.
Results: Of 66,993 deliveries, 67 (0.1%) were complicated by a preoperative diagnosis of probable appendicitis. Acute appendicitis was confirmed histologically in 45 (67%) of the 67 cases, for an incidence of 1 in 1493 pregnancies in this population. Distribution of suspected appendicitis in pregnancy was as follows; first trimester, 17 cases (25 cases); second trimester, 27 (40%); and third trimester, 23 (34%). Right-lower-quadrant pain was the most common presenting symptom regardless of gestational age (first trimester, 12 (86%) of 14 cases; second trimester, 15 (83%) of 18 cases; and third trimester, 10 (78%) of 13 cases). The mean maximal temperature for proven appendicitis was 37.6°C (35.5°C-39.4°c), in comparison with 37.8°C (36.7°C-38.9°C; not significant) for those with normal histologic findings. The mean leukocyte count in patients with proven appendicitis was 16.4 x 109/L (8.2-27.0 x 109/L), in comparison with 14.0 x109/L (5.9-25.0 x109/L) for patients with normal histologic findings. At the time of surgery, perforation had occurred in 8 cases. Of 23 patients at ³24 weeks’ gestational age, 19(83%) had contractions and an additional 3 patients (13%) had preterm labor with documented cervical change. One patient was delivered in the immediate postoperative period because of abruptio placentae.
Comment: The authors also attempted to validate the original study (1932) by Baer et al regarding change in pain location with advancing gestational age. They were unable to find any reliable sign or symptom that could aid in the diagnosis of acute appendicitis in pregnancy.
They were unable to corroborate the hypothesis of Baer et al that would suggest a right-upper-quadrant location for the pain of appendicitis in the third trimester.
As the appendix becomes obstructed by a coprolith, it distends and visceral afferent nerves are stimulated, causing constant poorly localized pain starting near the umbilicus and eventually migrating to McBurney’s point, which overlies the location of the appendix in most non-pregnant patients. As the full thickness of the appendiceal wall become necrotic and the serosa is damaged, the somatic neurons are stimulated, which localizes the pain to the right lower quadrant. This process appears to remain similar in pregnancy, contrary to the Baer theory and classical obstetric teaching. A high clinical suspicion is necessary to make the diagnosis, and because of overlap with normal pregnancy symptoms, a higher false-positive rate (30%) is not only acceptable but necessary to avoid unacceptable delay, with the possibility of increased morbidity and mortality rates.
Conclusion: Pain in the right lower quadrant of the abdomen is the most common presenting symptom of appendicitis in pregnancy regardless of gestational age. Fever and leukocytosis are not clear indicators of appendicitis in pregnancy and preterm labour is a problem after appendectomy, but preterm delivery is rare.
V Ware and B Denise Raynor (Atlanta, Georgia)
Transvaginal ultrasonographic cervical measurement as a predictor of successful labor induction.
Am J Obstet Gynecol, 2000; 182: 1030-2.
Objective: The authors purpose was to compare transvaginal cervical measurement and the Bishop score as indicators of duration of labor and successful induction of labor at term.
Study Design: This prospective observational study recruited women with singleton gestations scheduled for induction of labor at ³37 weeks. Transvaginal ultrasonographic measurement of cervical length was performed and the Bishop score was determined, each by operators masked to the other measurement. Data were collected on parity, gestational age, mode of delivery, induction agent, induction-to-delivery interval, Bishop score, and cervical length measurement.
Results: A total of 77 women were analyzed. Vaginal delivery occurred in 69%. Both Bishop score and cervical length showed linear correlation with duration of labor (R2= 0.43, P <.001; R2=0.48, P <.001; respectively). Women with cervical length <3.0cm had shorter labors (P<.001) and were more likely to be delivered vaginally (P<.001) women with a Bishop score >4 also had shorter labors and were more likely to be delivered vaginally, with similar P values. A logistic regression model identified cervical length and parity as the only independent predictors of vaginal delivery.
Conclusions: Both ultrasonographically measured cervical length and Bishop score predict duration of labor and likelihood of vaginal delivery. However, only cervical length and parity were independent predictors of mode of delivery.
M C Houston, B Denise Raynor (Atlanta, Georgia)
Postoperative morbidity in the morbidly obese parturient woman: Supraumbilical and low tranverse abdominal approaches.
Am J Obstet Gynecol, 2000; 182(5),p1033-1035
Objective: The authors purpose was to determine the differences in postoperative morbidity in obese women who had a supraumbilical or a Pfannenstiel incision at cesarean delivery.
Study Design: A case-control retrospective review was conducted of all patients who were at > 150% ideal body weight when undergoing cesarean delivery between 1989 and 1995 by means of either a supraumbilical or a Pfannenstiel incision. Patients were excluded if medical records were unavailable. A total of 15 women who had a supraumbilical incision and 54 who had a low transverse incision were included in the analysis. Antenatal complications were examined, as were age, weight, and training level of the surgeon. Postoperative complications were then compared.
Results: The groups were similar in age and antepartum complications. However, mean weight and percentage of ideal body weight in the supraumbilical group were both higher (P<.00001 and P <.0001, respectively), with the supraumbilical group 83 lb heavier on average. No significant differences were seen in any postoperative complication.
The use of incisional drains was uncommon; only 2 patients were fitted with subcutaneous Jackson-Pratt drains.
Material and methods: All patients received one prophylactic dose of antibiotics after umbilical cord clamping.
Comment: However, type of skin incision, vertical or Pfannenstiel, was not a significant determinant of total operative time.
The results of this retrospective review suggest that a supraumbilical incision presents no distinguishable advantage for decreasing morbidity over that of the low transverse incision. In 6 years at the institution, only 19 supraumbilical procedures were performed.
A supraumbilical abdominal incision does provide much-needed exposure and ease of performance. It should therefore be kept in the obstetrician’s repertoire as a viable alternative to the low tranverse approach in the morbidly obese patient.
Conclusion: Postoperative morbidity in morbidly obese women undergoing cesarean delivery does not differ between a supraumbilical approach and the low transverse abdominal incision.
R F Ford, J R Barton, et al (Lexington, Kentucky)
Demographics, management, and outcome of peripartum cardiomyopathy in a community hospital.
Am J Obstet Gynecol 2000; 182: 1036-8)
Objective : The purpose of this study was to describe the outcome of peripartum cardiomyopathy in patients cared for in a community hospital.
Study Design: The cases of peripartum cadiomyopathy treated at Central Baptist Hospital in Lexington, Kentucky, from January 1, 1992, to December 1, 1998, were reviewed.
Results: Eleven patients with peripartum cadiomyopathy were identified. The patient population was 91% white and 9% African American. Seventy-two percent of patients were nulliparous, and the prevalence of chronic hypertension was 27%. All patients were examined with echocardiography and met diagnostic criteria for the disease when this modality was used. The mean ejection fraction was 32% ± 10%. Invasive techniques used to assist in diagnosis included left ventricular catheterization (63%), right ventricular catheterization (54%), and cardiac biopsy (54%). One patient required cardiac transplantation. This patient also had an embolic stroke from a confirmed mural thrombus. No study patient died of the disease, and no other major complications were observed.
Three patients underwent cesarean delivery. Medical management consisted of diuresis, afterload reduction, inotropic support and anticoagulation. Angiotensin-converting enzyme inhibitors were used in 91% of the cases post partum. In the single case in which an angiotensin-converting enzyme inhibitor was not used, afterload reduction was provided by a calcium channel blocker. Digoxin was used in 6 patients, who also had therapeutic anticoagulation.
Comment: Hibbard et al proposed echocardiographic criteria to assist clinical criteria in establishing a diagnosis. These ultrasonographic criteria include an ejection fraction of < 45%, with fractional shortening of < 30% or an end-diastolic dimension of >2.7 cm/m2 or both of these.
Conclusion: The patient profile of peripartum cardiomyopathy in this study differed remarkably from profiles in published reports. Nulliparous white women have better outcomes than indicated by previous reports, probably because of the low frequency of co-existing chronic disease and a younger age at diagnosis.
C A Buccellato, C S Stika, et al (Chicago, Illinois)
A randomized trial of misoprostol versus extra-amniotic sodium chloride infusion with oxytocin for induction of labor.
Am J Obstet Gynecol, 2000; 182: 1039-44
Objective: Our purpose was to compare the efficacy and safety of misoprostol and extra-amniotic sodium chloride infusion with oxytocin for induction of labor.
In 1989 Schreyer et al described a technique of cervical ripening using a 26F Foley catheter inserted through the cervical os into the extra-amniotic space with infusion of isotonic sodium chloride. They showed that extra-amniotic sodium chloride infusion was as effective and safe as prostaglandin E2.
Misoprostol has also been shown to result in a similar or shorter induction to delivery time when compared with oxytocin, dinoprostone, intravaginal gel, intracerical get (Prepidil), and the dinoprostone vaginal insert (Cervidil).
Study Design: This randomized trial compared two methods of labor induction in women requiring cervical ripening. One hundred twenty-three women undergoing labor induction with a Bishop score £ were randomly selected to receive either misoprostol, 50 mg intravaginally every 4 hours, or extra-amniotic sodium chloride infusion. The primary outcome variable was the time interval from induction to vaginal delivery.
Material and Methods: The misoprostol regimen was therefore increased to 50 mg every 4 hours and a new randomization schedule was generated. The dose was repeated every 4 hours for a maximum of 4 doses, until the cervix was ³ 4 cm dilated, or 16 hours had elapsed. Oxytocin administration was begun with a delay of 4 hours after the last misoprostol dose.
Women randomly selected to have extra-amniotic sodium chloride infusion with oxytocin had a 26F Foley catheter with a 30-mL balloon placed aseptically through the internal os of the cervix into the extra-amniotic space. The balloon was inflated and the catheter fitted with an adapter through which isotonic sodium chloride was infused at a rate of 40mL/h. At the time of insertion of the extra-amniotic infusion catheter, intravenous oxytocin administration was begun at an initial dose of 2.0 mU/min and was increased at 15-minute intervals by 2.0 mU/min to a maximum dose of 36mU/min.
Results : Sixty-one women received extra-amniotic sodium chloride infusion and 62 women received misoprostol. The mean time interval from the start of induction to vaginal delivery was 15.0 ± 5,0 hours and 16.5 ± 7.2 hours for the extra-amniotic infusion and misoprostol groups, respectively (P, not significant). The cesarean delivery rate was not significantly different between the 2 groups (32.8% for the extra-amniotic infusion group; 19.4% for the misoprostol group). Maternal and neonatal outcomes were similar between the 2 groups.
Comment: In a number of other trials, investigators have expressed concern regarding the occurrence of tachysystole and hyperstimulation associated with misoprostol. Terbutaline was necessary for the treatment of hyperstimulation in 5 of the misoprostol patients.
Although the study did not formally examine cost differences between the sodium chloride-plus-oxytocin regimen and the misoprostol regimen, the very low cost of the misoprostol tablets makes this regimen fiscally attractive.
Conclusion: Both methods of induction are equally efficacious and result in similar maternal and neonatal outcomes.
Deborah A Wing, Alane S Park et al (Los Angeles, California, Honolulu, Hawaii
Limited clinical utility of blood and urine cultures in the treatment of acute pyelonephritis during pregnancy.
Am J Obstet & Gynec.June 2000, vol182: 1437-41
Objective: The purpose of this study was to determine the utility of urine and blood cultures in the clinical management of pregnant women with acute pyelonephritis.
Study Design: Data were pooled from three randomized controlled trials that were conducted at two university-based tertiary care centers and included 391 pregnant women with pyelonephritis. The results of urine and blood cultures were correlated with clinical management decisions, outcome, length of hospital stay, and cost.
Results: Results of 98% of urine cultures (382/291) and 99% of blood cultures (388/391) were available for analysis. The most common pathogen isolated was Escherichia coli, which was found in 79% of the urine cultures (300/382) and in 77% of the blood cultures (27/35). Susceptibility testing revealed 46% resistance to ampicillin; 7%, 2% and 0% resistances to first, second, and third generation cephalosporins, respectively; and 1% resistance to gentamicin. Six percent of the participants (25/391) required changes in antibiotic therapy, most commonly for persistent fever (6/25, 25%). Positive blood culture results directly influenced management by prolonging the duration of hospitalization, with means of 4.6 ± 2.6 hospital days for women with bacteremia and 2.6 ± 1.5 hospital days for women without bacteremia (P <.001) despite similar duration of symptoms.
Conclusion: Urine and blood cultures with sensitivity testing had limited utility in the clinical management of pregnant women with pyelonephritis. Decisions to change antibiotic treatment were affected more by clinical course than by culture results. The authors suggest that elimination of blood and urine cultures might simplify management and result in significant cost savings without compromising patient care.
Susan L Hendrix, V Schimp, et al (Detroit, Michigan)
The legendary superior strength of the Pfannenstiel incision: A myth?
Am J Obstet Gynecol. Vol.182, June 2000, p.1446-51
Objective : This study was undertaken to determine whether there is a difference in the frequency of fascial dehiscence between midline vertical lower abdominal and pfannenstiel incisions among women undergoing obstetric and gynecologic operations.
Study Design: A case-control study of 48 cases of fascial dehiscence complicating 17,995 major operations (8950 cesarean deliveries and 9405 gynecologic procedures) during a 6 year period at Wayne State University Hutzel Hospital, Detroit, was performed.
Results: Among the 48 patients who underwent repair of fascial dehiscence after a major obstetric or gynecologic operation, 27 were from the obstetric service and 21 were from the benign and cancer gynecologic services. Wound dehiscence occurred in 10 vertical incisions and 17 Pfannenstiel incisions among the obstetric patients and in 12 vertical and 9 Pfannenstiel incisions among the gynecologic patients. The risk for dehiscence incision (P=.39, 2-tailed). This finding was true for all patients (odds ration, 1.3; 95% confidence interval, 0.7-2.6), obstetric patients (odds ratio, 1.3; 95% confidence interval, 0.5-3.4), and gynecologic patients (odds ratio, 1.5;95% confidence interval, 0.5-4.0). Forty-seven of the 48 case patients had documented wound infections, compared with 1 of the 144 control subjects (P<.001, odds ratio, 37.8; 95% confidence interval, 14.8-96.8)
Conclusion: Wound infection was the most important risk factor for fascial dehiscence among women who underwent major obstetric and gynecologic operations. Our results do not support the long-held belief that Pfannenstiel incisions are stronger than lower abdominal vertical incisions and reduce the risk for fascial dehiscence.
Sean C Blackwell, Jerrie S Refuerzo, et al (Detroit, Michigan)
The relationship between nucleated red blood cell counts and early-onset neonatal seizures.
Am J Obstet Gynceol. Vol.182; June 2000, p.1452-7)
Objective: this study was undertaken to better define the timing of neurologic insult in neonates with early-onset seizures through evaluation of neonatal nucleated red blood cell levels.
Study Design: Medical records and the International Classification of Diseases, Ninth Revision codes were used to identify all term neonates with neonatal convulsions who were delivered was matched to the next 3 neonates who met he following criteria : gestational age ³37 weeks, no early onset seizures, birthweight ³2800 g, umbilical artery pH ³7.25, and a 5-minute Apgar score <7.Demographic characteristics, clinical factors, and mean initial nucleated red blood cell counts were compared between groups.
Results: During the 6-year study period, there were a total of 36,490 singleton term deliveries of infants who were alive at birth. Forty-five (0.1%) of these neonates had early-onset seizures. Thirty neonates with early-onset seizures met the inclusion criteria. Mean nucleated red blood cell counts (number of nucleated red blood cells per 100 white blood cells) for neonates with early-onset seizures were significantly increased compared with those of control neonates.
Comment: This suggests that the timing of the hypoxicischemic insult occurred from 48 hours to 7 days before delivery.
The possibility also remains that the etiologic insult may be related not to asphyxia but to another mechanism such as a maternal or intrauterine infectious process.
In conclusion, the finding of an increased nucleated red blood cell count in a neonate with development of early-onset seizures suggests a hypoxicischemic insult before the intrapartum period. This finding may aid in the defense of claims that suggest that suboptimal intrapartum care was given and that intervention would have prevented neurologic injury.
Conclusion : Our findings are suggestive of the hypothesis that neurologic injury leading to early-onset seizures often occurs before the intrapartum period.
Expert comments: This article could be useful for defence in medical negligence law-suit.
H Y How, B Jo Harris, et al (Cincinnati, Ohio and Louisvill,e Kentucky)
Is vaginal delivery preferable to elective cesarean delivery in fetuses with a known ventral wall defect?
Am J Ob stet Gynecol, vol.182, June 2000, p.1527-34.
Objective : The authors sought to test the hypothesis that vaginal delivery compared with elective cesarean delivery results in improved neonatal outcome in fetuses with a known isolated ventral wall defect.
Study Design: They performed a retrospective chart review.
Results : Between 1989 and 1999, they identified 102 infants with a confirmed antenatal diagnosis of an isolated ventral wall defect with either the diagnosis of an omphalocele or gastroschisis. Sixty-six infants were delivered by cesarean and 36 were delivered vaginally. There were no significant demographic differences between the study groups or between the two sites except than one center (Cincinnati) usually delivered these fetuses by cesarean whereas the other (Louisville) usually delivered such fetuses vaginally. Overall, there were a greater number of infants with gastroschisis than imphalocele (gastroschisis, n=71; omphalocele, n=31). After they controlled for primary versus staged closure of ventral wall defect and gestational age at delivery; the medians and interquartile ranges for cesarean and vaginal delivery were 39 (25,63) days versus 42 (26, 75) days, respectively (P =.32), for neonatal length of stay and 13 (9, 18) days versus 13 (9, 26) days, respectively (P=.16), for days to enteral feeding. After they controlled for the size of the defect and the amount of bowel resected, the odds of primary closure given a vaginal delivery was about half that given a cesarean delivery (odds ratio, 0.56; 95% confidence interval, 0.18-1.69), but this was not statistically significant. There was no statistically significant difference in the rates of neonatal death (2[3%]vs 2[6%]; P=.61) and neonatal sepsis (2[3%]vs 4[11%]; p=.18) for cesarean versus vaginal delivery. Maternal length of stay after delivery was found to be 1 day less after vaginal delivery (vaginal, 2(2,2) days; cesarean, 3(2,3) days; P=.0001]. There were 5 instances of maternal complications, and all 5 pregnancies were delivered by cesarean (P=.16).
Conclusion: Fetuses with an antenatal diagnosis of an isolated ventral wall defect may safely be delivered vaginally, and cesarean delivery should be performed for obstetric indications only.
V L Miller, S B Ransom, et al (Detroit, Michigan)
Multifetal pregnancy reduction: Perinatal and fiscal outcomes.
Am J Obstet Gynecol, vol.182, June 2000,p.1575-80
Objective: This study was undertaken to compare the birth outcomes of a multifetal pregnancy reduction population with those of other patients delivered at Hutzel Hospital, Detroit, and to determine the fiscal impact of the multifetal pregnancy reduction program.
Study Design: In a retrospective review patients who were delivered after multifetal pregnancy reduction were compared with a general obstetric population who were delivered at Hutzel Hospital from January 1, 1986, through June 30, 1998. Outcome data were determined through a comprehensive perinatal database. The c2 analysis was used to examine the relationship between gestational age and delivery group. Financial data were estimated from published reports of neonatal intensive care unit admissions, cost estimates for neonatal intensive care unit care, and charges for multifetal pregnancy reduction.
Results : Pregnancies reduced to triplets, twins and singletons had outcomes at least comparable to unreduced pregnancies starting at these numbers and substantially better than unreduced pregnancies with the same starting number. Financial estimates of hospitalization costs averted in the multifetal pregnancy reduction population exceeded $28 million.
Conclusion: Use of multifetal pregnancy reduction improved obstetric outcomes for pregnancies with multiple gestations and also was associated with significant fiscal savings.
E F Magnann, M Sanderson, et al (Jackson, Mississippi, South Carolina)
The amniotic fluid index, single deepest pocket, and two-diameter pocket in normal human pregnancy.
Am J Obstet Gynecol, vol.182, June 2000, p.1581-8)
Objective: This study was undertaken to determine normative values for amniotic fluid index, single deepest pocket, and 2-diameter pocket across gestation.
Study Design: Fifty patients with normal pregnancies at each gestational age between 14 and 41 weeks’ gestation were recruited prospectively and scanned once. Data were transformed into logarithmic (base10) values for analysis. Polynomial regression equations were used to predict the normal values for amniotic fluid index, single deepest pocket, and 2-diameter pocket across gestational age and to predict the weekly percentage changes.
Results: The mean amniotic fluid index, single deepest pocket, and 2-diameter values were significantly lower among patients at <37 weeks’ gestation (n-1150) than among those at ³37 weeks’ gestation (n=250; p<.001 for all comparisons). The calculated prevalences of oligohydramnios (amniotic fluid index £ 5cm, single deepest pocket <2cm, or 2-diameter pocket <15cm2) were significantly different (P<.0001) for the three techniques (8%,1 %, and 30%, respectively). Hydramnios (amniotic fluid index>24cm, single deepest pocket >8cm, or 2-diameter pocket >50cm2) was also diagnosed with significantly different (P<.0001) frequencies (0%,0.7% and 3%, respectively).
Conclusions: This is the largest prospective study to date to provide normative data for each of three ultrasonographic techniques used to assess amniotic fluid volume. The single deepest pocket appears to be the preferable method, because its use is least likely to lead to the false-positive diagnosis of either olioghydramnios or hydramnios.
C M Strom, Sstrom, et al (Chicago, Illinois)
Obstetric outcomes in 102 pregnancies after preimplantation genetic diagnosis.
Am J Obstet Gynecol, vol.182, June 2000, p.1629-32.
Objective: To determine whether preimplantation genetic diagnosis is associated with particular pregnancy or delivery complications.
Study Design : A total of 102 consecutive pregnancies after preimplantation genetic diagnosis by polar body removal performed at Illinois Masonic Medical Center resulting in 114 live births were analyzed. All patients were given a delivery and newborn questionnaire, and attempts were made to contact and question them regarding any pregnancy complications and type of delivery. Permission was obtained to examine medical records and discuss the patient’s pregnancy with her obstetrician when questions existed with respect to complications or indication for cesarean delivery.
Results: There were 85 singleton, 9 twin and 7 triplet pregnancies. Of the 7 triplet gestations, 3 couples elected multifetal pregnancy reduction to twins and healthy triplets were born to 4 couples between 32 and 36 weeks by cesarean delivery. Of the 80 singleton deliveries, 60(75%) progressed to term. Of these 60 term singleton deliveries, 34 were vaginal, 23 were cesarean (40%), and 3 delivery types were unknown. The incidence of small-for-gestational-age infants was 3% for neonates in the 60 term singleton deliveries and 7% in the entire cohort of 80 singleton deliveries. Only 3 pregnancy complications (other than premature delivery)were reported more than once. There were 3 instances each of gestational diabetes, intrauterine growth restriction, and pregnancy-induced hypertension.
There was 1 case each of HELLP (hemolysis, elevated liver enzymes, and low platelets) syndrome, congestive heart failure, mild oligohydramnios, and abruptio placentae. The indications for cesarean delivery were (in descending order) failure of labor to progress (n=7), fetal distress (n=4), placenta previa (n=4), elective repeat cesarean delivery (n=4), triplets (n=3), uterine scarring (n=3), 1 twin in the breech position (n=3), failed forceps delivery (n=2), and a variety of other indications that occurred in only 1 patient each. All preimplantation genetic diagnoses were confirmed by prenatal or postnatal testing. No diagnostic errors were made in this cohort of patients or in any patients undergoing preimplantation genetic diagnosis having polar body removal in our center.
Conclusions: Preimplantation genetic diagnosis is associated with a risk of multiple gestations, cesarean delivery, and placenta previa. Cesarean delivery rates and multiple gestation rates are comparable to those of patients undergoing in vitro fertilization in general. The preimplantation genetic diagnosis itself does not seem to cause an increased risk for any particular pregnancy complication, with the possible exception of placenta previa, which was seen in 4% of patients.
H N Winn, M Chen, et al (St. Louis, Missouri)
Neonatal pulmonary hypoplasia and perinatal mortality in patients with midtrimester rupture of amniotic membranes – A critical analysis.
Am J Obstet Gynecol. Vol.182, June 2000, p.1638-44
Objective : To critically assess the risk factors for neonatal pulmonary hypoplasia and perinatal death in patients with preterm rupture of the amniotic membranes from 15 to 28 weeks’ gestation.
Study Design: This was a prospective cohort study. The study patients had preterm rupture of the amniotic membranes at 15 to 28 weeks’ gestation and were without fetal anomalies, multiple gestation, and oligohydramnios before rupture of the membranes. The amniotic fluid volume index was determined at admission and weekly afterward until delivery.
Results: The incidence of pulmonary hypoplasia was 12.9% (21/163). The overall perinatal mortality rate was 54% (11/163). Logistic regression analysis revealed the following: (1) Gestational age at rupture of the membranes, the latency period, and either the initial or the average amniotic fluid index have significant influence on the development of pulmonary hypoplasia; (2) gestational age at rupture of the membranes and latency period are significant factors in predicting perinatal death.
Conclusions: In this large population of patients with rupture of membranes at 15 to 28 weeks’ gestation, gestational age at rupture of the membranes, latency period, and amniotic fluid index were important independent predictors of neonatal pulmonary hypoplasia. In addition, gestational age at rupture of the membranes and latency period were important independent determinants of perinatal death. Expectant management of patients with preterm rupture of the amniotic membranes during this gestational age interval was associated with improved perinatal survival, even though it may increase the risk of pulmonary hypoplasia.
B K Rinehart, D A Terrone, et al (Jackson, Mississppi)
Lack of utility of standard labor curves in the prediction of progression during labor induction.
Am J Obstet Gynecol, vol.182, June 2000, p.1520-6
Objective: This study was undertaken to determine whether patients undergoing labor induction can be reliably evaluated by means of standard labor assessment curves.
Study Design: In this retrospective chart review of 123 patients who underwent cervical ripening and induction of labor, Friedman’s standard labor curves were used for comparison. Statistical analysis was performed with the Student test.
Results : Nulliparous and parous patients undergoing cervical ripening spent more time in active-phase labor than standard expectations of labor progression would indicate (12.7 ± 7.8 vs 5.9 ± 3.4 hours for nulliparous women, P <.001; 7.9 ± 6.4 vs 2.5 ± 1.5 hours for parous women, P <.001). Nulliparous and parous patients who were delivered vaginally spent more time in active labour than did their respective standard historicla control populations (10.3 ± 8.0 vs 5.9 ± 3.4 hours for nulliparous women, P <.001; 7.0 ± 6.0 vs 2.5 ± 1.5 hours for parous women, P <.001)
Conclusion: Standard methods for the evaluation of labor adequacy and prediction of the likelihood of vaginal delivery may not apply to patients undergoing cervical ripening.
T K Lau, T Y Leng, et al (Shatin, Hong Kong)
Effect of external cephalic version at term on fetal circulation
Am J Obstet Gynecol, May 2000, 182 : 1239-42
Objective: The authors sought to investigate the sub-clinical effect of external cephalic version on fetal circulation.
Study Design: A prospective observational study was conducted on 136 subjects who had external cephalic version at or beyond 36 weeks of gestation without clinical complication. Doppler ultrasonographic studies of the umbilical and middle cerebral circulations were performed before and after the external cephalic version. The following Doppler indexes were measured (1) the pulsatility index of the umbilical artery, which represents disturbance of placental circulation, and (2) the pulsatility index of the fetal middle cerebral artery, which represents fetal response. The Wilcoxon signed rank test was used for all statistical analyses.
Results: There was no significant difference in pulsatility index of the umbilical artery before and after external cephaclic version (P=.674). There was a statistically significant reduction in the pulsatility index of the middle cerebral artery after external cephalic version (P=.029), among those in whom the external cephalic version was considered to be difficult (P=.038), and when the placenta was posteriorly located (P=.028). The reduction in pulsatility index was not related to whether the external cephalic version was successful. In all cases the Doppler indexes remained within the normal ranges, and there were no associated fetal complications.
Conclusion: External cephalic version was not associated with any significant disturbance of placental resistance to blood flow. Conversely, external cephalic version was associated with a significant reduction in the pulsatility index of the middle cerebral circulation, especially among the multiparous women, after a difficult procedure or in those with a posterior placenta. This probably represents a normal fetal physiologic response to manipulation of the fetal head.
Matthias David Matthias M. Walka, Bernhard Schmid, Pranav Sinha, Siegfried Veit, and Werner Lichtenegger,
Nitroglycerin Application During Cesarean Delivery : Plasma Levels, Fetal/Maternal Ratio of Nitroglycerin, and Effects in Newborns
Am J. Obstet Gynecol April 2000, Volume 182, Number 4, Pgs. 955-961
Objective -Over the last decade, there have been several reports of successful obstetric use of nitroglycerin as a ticolytic. Nitroglycerin, which is also known
as glycerol trinitrate, may be administered before, during, or after delivery and is well suited for use as a short-term tocolytic agent before external and internal change to extract a retained placenta or to correct a uterine inversion, as well as during cesarean delivery.
They sought to investigate maternal and fetal nitroglycerin metabolization and to assess the clinical condition of neonates after intravenous nitroglycerin application during cesarean delivery.
Study Design – At the time of the uterine puncture incision, either 0.25 mg or 0.5 mg nitroglycerin or a physiologic sodium chloride solution was administered as an intravenous bolus. Plasma concentrations of nitroglycerin and its metabolites were measured in maternal venous blood and in umbilical blood samples taken immediately after cord clamping. Arterial blood pressure, pulse rates, and Apgar scores were recorded for the neonates 1, 5, and 10 minutes after birth.
Conclusion – The level of nitroglycerin in umbilical plasma was two to three orders of magnitude lower than that found in maternal plasma and clearly in a subtherapeutic range. There was no indication that prenatal application of nitroglycerin to facilitate obstetric management is hazardous for neonates.
Doses between 0.05 mg and 1.85 mg glycerol trinitrate have been used successfully for various indications, both subpartum and postpartum, and doses have been applied intravenously, as patches, and as sublingual sprays.
The marked difference between venous and arterial levels of glycerol trinitrate and its metabolites in the umbilical cord indicates that the process of nitrate breakdown is already functioning well before birth.
They conclude that there is no evidence of major risk to the neonate from administration of an intravenous bolus of 0.25 or 0.5 mg glycerol trinitrate to the mother during a cesarean delivery.
Renee Lacroix, EricaEason, and Ronald Melzack, [ From the Department of Psychology, McGill University, and the Departments of Obstetrics and Gynecology and Clinical Epidemiology, University of Ottawa
Nausea and Vomiting during Pregnancy : A Prospective Study of its Frequency, Intensity, and Patterns of Change
Am J. Obstet Gynecol April 2000, Volume 182, Number 4, Pgs. 931-937
Objective – Our purpose was to provide a detailed description of patterns of nausea and vomiting of pregnancy.
Study Design – A prospective study was performed with 160 women who provided daily recordings of frequency, duration, and severity of nausea and vomiting.
Results – Seventy-four percent of women reported nausea lasting a mean of 34.6 days. “Morning sickness” occurred in only 1.8% of women, whereas 80% reported nausea lasting all day. Only 50% of women were relieved by 14 weeks’ gestation; 90% had relief by week 22. Data based on the McGill Nausea Questionnaire indicate that the nausea experienced by pregnant women is similar in character and intensity to the nausea experienced by patients undergoing cancer chemotherapy.
Conclusions- Traditional teachings about nausea and vomiting of pregnancy are by our findings. Standardized tools for measuring the distribution, duration, and intensity of nausea are applicable to the study of nausea and vomiting of pregnancy and could be used in clinical trials to assess pallative measures
Brian M. Casey, Donald D. McIntire, et al [From the Departments of Obstetrics and Gynecology and Radiology, University of Texas Southwestern Medical Center]
Pregnancy Outcomes After Antepartum Diagnosis of Oligohydramnios at or Beyond 34 Week’s Gestation
Am J. Obstet Gynecol April 2000, Volume 182, Number 4, Pgs. 909-912
Objective – Our purpose was to assess whether antepartum oligohydramnios is associated with adverse perinatal outcomes.
Study Design – Women delivered between July 1, 1991, and September 30, 1996, who underwent ultrasonography at > 34 weeks’ were analyzed. Oligohydramnios was defined as an amniotic fluid index < 50 mm. Perinatal outcomes in pregnancies with oligohydramnios were compared with those with an amniotic fluid index of >50 mm.
Results – In our analysis of 6423 pregnancies, 147[ 2.3%] were complicated by oligohydramnios. This complication was associated with increased labor induction [42% vs 18%; p<.001], stillbirth [1.4% vs 0.3%; p<.03] , nonreassuring fetal heart rate [48% vs 39%; p,.03], admission to the neonatal intensive care nursery [7 vs 2%; p,.00], meconium aspiration syndrome [1% vs 0.1%; p,.001], and neonatal death [5% vs 0.3%; p<.001]
Conclusion – Antepartum oligohydramnios is associated with increased perinatal morbidity and mortality.
The AFI was first described in 1987, and gestational age-based nomograms were developed by 1993. AFI values of <50 mm are meaningful in the prediction of adverse pregnancy events. Indeed, use of the AFI to predict fetal
well-being is complicated by the imprecise nature of its measurement, as well as by individual physician thresholds for pregnancy interventions.
The association between oligohydramnios and significant perinatal morbidity and mortality is significant.
K D Heyborne, Englewood, Colorado
Preeclampsia prevention: Lessons from the low-dose aspirin therapy trials
Am J Obstet Gynecol, 183(5), Sept.2000, p.523.
The ability of low-dose aspirin therapy to prevent preeclampsia is controversial. The 19 randomized, placebo-controlled trials of low-dose aspirin therapy reported in the literature were categorized according to the risk factors of the women studied-nulliparity, underlying medical illness, poor obstetric history, and multiple gestation. Low-dose aspirin therapy reduced the incidence of preeclampsia among women with poor obstetric histories and among high-risk nulliparous women but was ineffective among women with underlying medical illness. It was marginally effective among low-risk nulliparous women, and benefits for women with multiple gestations. The differential effects of low-dose aspirin therapy in the various risk groups are probably a result of varying roles in the groups of abnormal arachidonic acid metabolism in mediating preeclampsia. It is premature to abandon the use of low-dose aspirin therapy for preeclampsia prevention.
Recommendation regarding low-dose aspirin therapy use for preeclampsia prevention
Low dose aspirin recommended
Nulliparous, low risk
Minimal clinical benefit.
Nulliparous, high risk
Need better screening tests to identify women who will benefit; consider use in nulliparous women with serum hCG concentration >3.0 multiples of the median.
High risk, medical
High risk, obstetric
High risk, multiple Gestation
More studies needed
E Ekerhovd, M Brannstrom et al (Goteborg, Sweden)
Nitric oxide synthases in the human cervix at term pregnancy and effects of nitric oxide on cervical smooth muscle contractility.
Am J Obstet Gynecol, Sept.2000; 183: 610-6
Objective: The purpose of the study was to determine whether a nitric oxide-generating system exists in the uterine cervix at term pregnancy and to study the effects of nitric oxide on contracting cervical strips.
Study Design: Tissue specimens were obtained from the cervices of women after deliveries and at elective cesarean deliveries. Immunohistochemcial techniques and immunoblotting were used to identify isoforms of nitric oxide synthase. The effects of nitric oxide on cervical contractility were examined by the addition of nitroglycerin or spermine NONOate [(Z)-1-(N-[3-aminopropyl]-N-[4-(3-aminopropyl-ammonio)butyl]-amino)-diazen-1-ium-1,2-diolate] to organ baths.
Results: Immunohistochemical examination demonstrated positive staining for both endothelial and inducible nitric oxide synthase. Both isoforms of nitric oxide synthase were clearly detectable by immunoblotting. Significant inhibition of contractile activity (10-7-10-5 mol/L) was observed when nitroglycerin or spermine NONOate was administered.
Conclusion: An endogenous nitric oxide system is present in the uterine cervix at term, and this tissue is responsive to nitric oxide, which causes relaxation of the cervical muscle.
Cervical ripening accomplished by local application of prostaglandins is commonly used to facilitate first-trimester surgical termination of pregnancy or to induce labor at term. A recently published randomized trial of the nitric oxide donor isosorbide mononitrate versus the prostaglandin analog gemeprost demonstrated that this specific nitric oxide donor not only caused adequate cervical ripening but also had fewer side effects than gemeprost. On the basis of their results, which have demonstrated the existence of a functional nitric oxide system within the human uterine cervix at term, the authors propose that there may also exist a clinical role for locally administered nitric oxide donors in induction of cervical ripening in pregnant women at term.
Nina Markovic, Roberta B Ness et al (Pittsburgh, Pennsylvania0
Substance use measures among women in early pregnancy
Am J Obstet Gynecol, 183: Sept.2000: 627-32
Objective : The authors purpose was to compare self-reported and biochemical measures for tobacco, marijuana and cocaine exposures among women early in pregnancy.
Conclusions: Urinary assays were equally likely to be positive among women reporting never use and those reporting past use of tobacco, marijuana, or cocaine. Thus women with a positive biologic assay result were as likely to deny use of tobacco as they were to deny marijuana, or cocaine.
J Waugh, I J Perry et al (Leicester and London, UK and Cork, Ireland)
Birth weight and 24-hour ambulatory blood pressure in nonproteinuric hypertensive pregnancy
Am J Obstet Gynecol, Sept.2000; 183: 633-7.
Objective: The aim of this study was to examine the relationship between maternal ambulatory blood pressure monitor measurements during pregnancy and birth weight in a population of women considered to have hypertension according to conventional antenatal clinic measurement.
Study Design: A total of 237 women were found to have hypertension (blood pressure ³140/90mm Hg) without significant proteinuria during examination in the antenatal assessment area. Sequential -day unit blood pressure recordings and a 24-hour automated ambulatory blood pressure recording were performed, and the results were compared with the principal outcome measure of birth weight.
Results: A significant inverse association (gradient, -13.5; 95% confidence interval -23.4 to -3.6) was found between daytime ambulatory diastolic blood pressure measurement and birth weight. An increase of 5mm Hg in daytime mean diastolic blood pressure was associated with a fall in birth weight of 68.5g. This association remained after adjustment for potential confounders that included maternal age, maternal weight, smoking status, ethnicity, and gestational age at delivery. No such association was found between obstetric day unit assessment of blood pressure and birth weight.
Conclusion: There is a significant association between blood pressure and birth weight in nonproteinuric hypertensive pregnancies. The best predictor of this association is the daytime mean ambulatory diastolic blood pressure measurement. This is further evidence that maternal blood pressure may be an important confounding and potentially genetic variable in the association between birth weight and subsequent adult hypertension.
A Pascual, I Bruna, et al (Madrid, Spain)
Absence of maternal-fetal transmission of human immunodeficiency virus type 1 to second-trimester fetuses.
Am J Obstet Gynecol; 183: Sept.2000; 638-42.
Objective: The aim of this study was to evaluate the contribution of in utero infection to the vertical transmission of human immunodeficiency virus type-1 during the second trimester.
Study Design: The authors examined fetal tissues from 21 second-trimester prostaglandin-induced abortions among human immunodeficiency virus type1-infected women and compared the fetal vertical transmission rates with those among children born to human immunodeficiency virus -seropositive women. The presence of human immunodeficiency virus type1 nucleic acid sequences was investigated with two different highly sensitive polymerase chain reaction techniques in tissue samples from the fetal thymus, lung, and brain.
Results: No human immunodeficiency virus type1 deoxyribonucleic acid was detected in any of the samples.
Conclusion: The absence of human immunodeficiency virus type1 in all fetuses in their study is compatible with a low rate of maternal-fetal transmission during the second trimester of pregnancy.
D S McKenna, G M Wittber, et al (Columbus, Ohio)
The effects of repeat doses of antenatal corticosteroids on maternal adrenal function.
Am J Obstet Gynecol, Sept.2000; 183: 669-73
Objective: The purpose of this study was to determine whether repeated doses of maternal corticosteroids suppress the maternal hypothalamic-pituitary -adrenal axis.
Study Design: The low-dose corticotropin stimulation test (1.0 mg intravenously) was administered a median of 3 days after the last betamethasone dose to 18pregnant women who had received at least 2 weekly courses of antenatal betamethasone and to 6 control subjects matched for gestational age who had not received antenatal corticosteroids.
Results: The mean basal cortisol level was significantly depressed among women who had received betamethasone with respect to control subjects (1.9 ± 1.5 vs 26.5 ± 6.2 mg/dL; P<.001). The maternal cortisol level after corticotropin stimulation was significantly lower in all women who had received betamethasone (P<.001). The mean time to attainment of peak cortisol level was significantly longer among women who had received betamethasone than among control subjects (37 ± 6.8 vs 27.4 ± 1.6 minutes; P<.001).
Conclusions: Repeated courses of betamethasone lead to barely detectable maternal basal cortisol levels and secondary adrenal insufficiency.
Comment: This study indicates that in most cases basal 8AM cortisol levels during the third trimester of pregnancy can be used to accurately diagnose secondary adrenal insufficiency. The low-dose corticotropin stimulation test can be used when basal levels fall between 3 and 19 mg/dL.
The effects on human development from long-term maternal corticosteroid administration are uncertain. Antenatal corticosteroid should be repeated only in those pregnancies at the highest risk for preterm delivery. Furthermore, there are no data to support the use of corticosteroids for prophylactic indications.
Kathryn L. Reed, and Caroline F. Anderson, [ From the Department of Obstetrics and Gynecology, Arizona Health Sciences Center ]
Changes in Umbilical Venous Velocities with Physiologic Perturbations
Am J. Obstet Gynecol April 2000, Volume 182, Number 4, Pgs. 835-840
Objective – The purpose of this study was to determine the direction of transmission of umbilical venous Doppler flow velocity changes in human fetuses.
Study Design – Strip chart recordings of simultaneously measured umbilical arterial and venous velocities were examined at two sites in the umbilical cord, one near the fetus [ proximal] and one near the placenta [distal]. Fetuses with venous pulsations or breathing episodes were included. At both locations time from venous pulsation to arterial systole was measured in fetuses with venous pulsations and duration of phase delay between arterial diastolic velocity minimum and venous velocity minimum was measured in fetuses with breathing episodes.
Results – In 21 fetuses with venous pulsations, the pulsations occurred earlier in the cardiac cycle at proximal sites [0.12 + 0.04 second before systole] and later at distal sites [0.02 + 0.04 second before systole; p<.001]. Phase delays in venous velocities in the 5 fetuses with breathing episodes were also longer at distal sites than at proximal sites [P<.011].
Conclusion – changes in umbilical venous velocities occurred earlier at sites that were closer to the fetus. These findings suggest that changes in umbilical venous velocities originate in the fetal venous system and are transmitted to, rather than from, the placenta.
Vaccine against cervical cancer virus passes phase I trials
BMJ, Vol.322, March 3, 2001, p.510
Cervical cancer affects over 400,000 women a year worldwide and results in the death of 200,000 of them. It is caused by infections with oncogenic strains of the human papillomavirus. This virus is sexually transmitted.
A vaccine against HPV16, the most prevalent strain of the human papillomavirus found in cervical cancers, has passed phase I trials.
Henderson-Smart, Leila Duley, David Henderson, Smart et al
Antiplatelet drugs for prevention of pre-eclampsia and its consequences: systematic review.
BMJ, Vol.322, Feb.10, 2001. P.329
The cause of pre-eclampsia remains unknown, but it is associated with deficient intravascular production of prostacyclin, a vasodilator and excessive production of thromboxane, a platelet derived vascoconstrictor and stimulant of platelet aggregation. These observations led to the hypothesis that antiplatelet drugs might prevent or delay development of pre-eclampsia. This systematic review was done to assess the effects of antiplatelet drugs for prevention of pre-eclampsia and its complications.
The review included randomised trials involving women at risk of pre-eclampsia and its complications allocated to antiplatelet drugs, versus placebo or no antiplatet drug.
The conclusion was that antiplatelet drugs, largely low dose aspirin, have small to moderate benefits when used for prevention of pre-eclampsia.
M A Esposito, C A Meniham and M P Malee (Providence, Rhode Island)
Association of interpregnancy interval with uterine scar failure in labor: A case-control study.
Am J Obstet Gynecol, Nov.2000; 183: 1180-3
Objective: The aim of this study was to determine whether a short interpregnancy interval is associated with uterine scar failure in laboring patients with previous low transverse cesarean delivery.
Study Design : This was a case-control study of uterine scar failures among laboring patients with previous low transverse cesarean delivery. Control patients underwent abdominal delivery during labor after failure of an attempted vaginal birth after cesarean delivery in the same month as case patients.
Results: An interpregnancy interval of <6months was significantly more prevalent among case patients with uterine scar failure (P=.02). Mean interpregnancy interval was less in all cases of uterine scar failure (P=.06)
DJ Ravasia, S L Wood, and J K Pollard (Calgary, Alberta, Canada)
Uterine rupture during induced trial of labor among women with previous cesarean delivery.
Am J Obstet Gynecol, Nov. 2000, 183: 1176-9
Objective: This study was undertaken to compare the rates of uterine rupture during induced trials of labor after previous cesarean delivery with the rates during a spontaneous trial of labor.
Study Design: All deliveries between 1992 and 1998 among women with previous cesarean delivery were evaluated. Rates of uterine rupture were determined for spontaneous labor and different methods of induction.
Results : Of 2119 trials of labor, 575 (27%) were induced. The overall rate of uterine rupture was 0.71% (15/2119). The uterine rupture rate with induced trial of labor (8/575; 1.4%) was significantly higher than with a spontaneous trial of labor (7/1544; 0.45%l P=.0004). Uterine rupture rates associated with different methods of induction were compared with the rate seen with spontaneous labor and were as follows:
Prostaglandin E2 gel, 2.9%(5/172; P=.004) intracervical Foley catheter, 0.76% (1/129; P=.47); and labor induction not requiring cervical ripening , 0.74% (2/274; P=.63). The uterine rupture rate associated with inductions other than with prostaglanding E2 was 0.74% (3/474; P=.38). The relative risk of uterine rupture with prostaglandin E2 use versus spontaneous trial of labor was 6.41(95% confidence interval, 2.06-19.98).
Conclusion: Induction of labor was associated with an increased risk of uterine rupture among women with a previous cesarean delivery, and this association was highest when prostaglandin E2 gel was used.
F TH Lim, S A Scherjon, et al (Leiden, The Netherlands)
Association of stress during delivery with increased numbers of nucleated cells and hematopoietic progenitor cells in umbilical cord blood.
Am J Obstet Gynecol, Nov.2000; 183: 1144-51
Objective: Umbilical cord blood can be used as a source of bone marrow repopulating cells for allogeneic stem cell transplantation. Large variations in the frequencies of white blood cells and hematopoietic progenitor cells have been found for umbilical cord blood. These variations may be due in part to specific circumstances during labor and delivery.
Study Design: In this study, authors analyzed the relationship between stress factors occurring during parturition and the frequencies of nucleated cells, leukocyte subsets, CD 34+ cells, and hematopoietic progenitor cells in umbilical cord blood from children with lower venous pH.
Conclusion: Longer duration stress during delivery increased the numbers of nucleated cells, granulocytes, CD34+ cells, and hematopoietic progenitor cells, possibly by causing mobilization of various cell populations by endogenous cytokines. As long as umbilical cord blood harvesting does not interfere with the delivery, umbilical cord blood collected after stressful deliveries may provide optimal units for hematopoietic stem cell transplantation.
R O Bahado-Singh, S Shahabi, M J Mahoney (New Haven, Connecticut)
Comparison of urinary hyperglycosylated human chorionic gonadotropin concentration with the serum triple screen for Down syndrome detection in high-risk pregnancies.
Am J Obstet Gynecol, Nov.2000; 183: 1114-8.
Objective: Both modest screening performance and declining patient and physician acceptance have stimulated interest in alternative markers to the triple screen for the detection of Down syndrome. Authors purpose was to compare the concentration of a single urinary analyte, hyperglycosylated human chorionic gonadotropin, with the serum triple screen (a-fetoprotein, human chorionic gonadotropin, and unconjugated estriol concentrations combined with age) for second-trimester Down syndrome detection.
Study Design: Urine and blood were obtained from pregnant women in the second trimester undergoing genetic amniocentesis. Urinary hyperglycosylated human chorionic gonadotropin concentration and serum triple-screen values were measured. Individuals undergoing amniocentesis because of abnormal triple screen results were excluded. Individual Down syndrome risks on the basis of urinary hyperglycosylated human chorionic gonadotropin concentration plus maternal age and on the basis of the triple-screen results were calculated.
For each algorithm the sensitivity and false-positive rate for Down syndrome detection at different risk thresholds were determined. From these values receiver operating characteristic curves were constructed, and the area under the curve was determined for each algorithm. Finally, the performance of a new combination in which urinary hyperglycosylated human chorionic gonadotropin concentration replaced serum human chorionic gonadotropin concentration in the triple screen was ascertained.
Conclusion: The performance of urinary hyperglycosylated human chorionic gonadotropin concentration was statistically superior to that of the serum triple screen in a high-risk population. The use of urinary hyperglycosylated human chorionic gonadotropin concentration as an alternative test or substitution of this measurement for serum human chorionic gonadotropin concentration in the triple screen would improve diagnostic accuracy and address many current concerns related to the triple screen.
M C W illiams, W F. O’Brien , R N Nelson and W N Spellacy (Tampa, Florida)
Histologic chorioamnionitis is associated with fetal growth restriction in term and preterm infants.
Am J Obstet Gynecol, Nov.2000, 183: 1094-9
Objective: Authors aim was to evaluate associations between chorioamnionitis and fetal growth restriction in infants enrolled in the Collaborative Perinatal Period.
Study Design: A total of 2579 nonanomalous, singleton infants delivered at 28 to 44 weeks’ gestation with chorioamnionitis were matched 1:3 for ethnicity, gestational age, parity, and maternal cigarette use (all of which were correlated with both chorioamnionitis and markers of fetal growth restriction) with 7732 control infants. Moderate or marked leukocytic infiltrates of the placenta defined chorioamnionitis. Birth weight, length, head circumference, weight/length ratio, ponderal index, and birth weight/head circumference ratio in the lowest 5th percentile were markers of fetal growth restriction. Placental weight and the birth weight/placental weight ratio were also evaluated.
Results: Compared with data on matched control infants, histologic chorioamnionitis was associated with all markers of fetal growth restriction and with low birth weight/placental weight ratios (odds ratios, 1.3-1.7). The strongest associations were found at 28 to 32 weeks’ gestation (odds ratios, 2.2-11). Attributable risks for several markers of fetal growth restriction exceeded 50% in infants born at <33 weeks’ gestation.
Conclusion: Histologic chorioamnionitis is associated with multiple markers of fetal growth restriction with stronger associations noted in prematurity.
K A Eddleman, JL Stone et al (New York,)
Chorionic villus sampling before multifetal pregnancy reduction.
Am J Obstet Gynecol, Nov.2000; 183: 1078-81
Objective: This study was undertaken to determine the technical feasibility and accuracy of chorionic villus sampling before multifetal pregnancy reduction and to determine whether sampling increases the pregnancy loss rate after the reduction procedure.
Study Design: Between January 22, 1986, and January 20, 2000, a total of 1183 patients underwent first-trimester multifetal pregnancy reduction at Mount Sinai Medical Center. Chorionic villus sampling was attempted in 86 patients before the reduction procedure. Information on the technical success and accuracy of chorionic villus sampling, as well as pregnancy outcome, was collected on all patients. Pregnancy loss rates before 24 weeks’ gestation in patients undergoing chorionic villus sampling before multifetal pregnancy reduction were compared with rates in patients not undergoing sampling.
Results: chorionic villus sampling was successfully completed in 85 (98.8%) of 86 patients in whom sampling was attempted. Of 166 fetuses, 165 (99.4%) were successfully sampled. Of 165 fetuses, 3 (1.8%) had karyotypic abnormalities. Sampling errors were probably made in 2 (1.2%) of 165 fetuses. Of the 73 patients who have been delivered or are beyond 24 weeks’ gestation, only 1 patients (1.4%) had a pregnancy loss after the multifetal pregnancy reduction.
Conclusion: Chorionic villus sampling before multifetal pregnancy reduction is technically feasible and accurate, with an acceptably low sampling error rate. Chorionic villus sampling before multifetal pregnancy reduction appears to be safe and does not increase the risk of loss after the reduction procedure.
Comment: Authors suggest that in the presence of antenatal twin discordance HC/AC asymmetry may be a useful marker for identifying twin pregnancies at particular risk of perinatal morbidity and death.
A.Buchbinder, M Miodovnik, S McElvy et al (Dept. of Obstetric & Gynecology, Univ. of Cincinnati, Ohio and New York)
Is insulin lispro associated with the development or progression of diabetic retinopathy during pregnancy?
Am J Obstet Gynecol, Nov.2000; 183: 1162-5
Objective: The study was designed to determine whether there is an association between the use of insulin lispro during pregnancy and the development or progression of diabetic retinopathy.
Study Design: This observational cohort study included women with type 1 diabetes mellitus, who were enrolled in the diabetes mellitus in pregnancy program and were treated with insulin lispro during pregnancy. The authors compared these women with a historical cohort (n=42) who were treated with regular insulin during pregnancy. All patients underwent ophthalmologic examinations before 24 weeks gestation and post partum, and retinopathy was graded according to a previously defined scale.
Conclusion: These preliminary findings provide no evidence that insulin lispro treatment during pregnancy is associated with the development of progression of diabetic retinopathy.
U M Reddy, M M DiVito J C Armstrong et al (Dept. of Obst. &Gyn. Philadelpia, Pennsylvania)
Population adjustment of the definition of the vaginal birth after cesarean rate.
Am J Obstet Gynecol, Nov.2000; 182:1166-9
Objective : The vaginal birth after cesarean delivery rate is calculated with a denominator equal to the number of all women who give birth after a previous cesarean delivery, including those who are not candidates for a trial of labor. The authors evaluated the impact of adjustment for noncandidates for a trial of labor on vaginal birth after cesarean delivery rates.
Study Design: All women with a previous cesarean delivery who were delivered during 1998 were classified as either candidates or noncandidates for a trial of labor. An adjusted vaginal birth after cesarean delivery rate was calculated by eliminating noncandidates for a trial of labor from the denominator. The percentage of noncandidates for a trial of labor, the vaginal birth after cesarean delivery rate, and the adjusted vaginal birth after cesarean delivery rate were compared among 3 clinical services.
Conclusion: For accurate comparison of vaginal birth after cesarean delivery rates among providers it is essential to account for patient risk status in the vaginal birth after cesarean delivery definition through the elimination of noncandidates for a trial of labor.
Definitions of the vaginal birth after cesarean delivery (VBAC) rate, adjusted VBAC rate, and VBAC success rate.
VBAC Rate = No. of VBACs X 100
No. of women with prior cesarean deliveries.
Adjusted VBAC Rate = No. of VBACs X 100
(No. of women with prior cesarean deliveries –
VBAC Success Rate = No. of VBACs X 100
(of trial of labor after
cesarean delivery) No. of women who had trial of labor after
A.I. Whitsel, E C Capeless, D E Abel and G S Stuart (Burlington, Vermont)
Adjustment for case mix in comparisons of cesarean delivery rates: University versus community hospitals in Vermont.
Am J Obstet.Gynecol, Nov.2000; 183: 1170-5
Objective: The authors objective was to determine whether case mix model adjustment would help to explain differences in cesarean delivery rates between community and university hospitals. The authors also wished to define a patient population in which the cesarean delivery rate would be more reflective of individual practice patterns than of obstetric or medical risk.
Study Design: Established risk factors for cesarean delivery were identified by retrospective chart review at two community hospitals (designated A and B) and a university hospital. Each delivery was assigned exclusively to 1 of 6 risk categories: (1) multiple gestation, (2) fetal malpresentation, (3) delivery at <36 weeks gestation, (4) not suitable for trial of labor, and (5) term delivery (³ 36 weeks gestation) without medical complications.
Parity and history of cesarean delivery further subdivided these categories into a total of 18 unique subgroups. Case mix was defined as the distribution of patients into each subgroup. Patients assigned to the categories of multiple gestation, fetal malpresentation, delivery at <36 weeks gestation, and not eligible for trial of labor were considered to compose the group at high risk for cesarean delivery. The remaining patients composed the group at low risk for cesarean delivery.
Conclusion: The case mix model provides a more accurate method of comparing cesarean delivery rates between community and university hospitals. The low-risk group of patients discriminated in this model represents a population in which the cesarean delivery rate may be more reflective of individual practice patterns than of maternal or fetal risks.
C M Zelop, T D Shipp, J T Repke, A Cohen and E Lieberman (New York, Boston, Massachusetts and Omaha, Nebraska)
Effect of previous vaginal delivery on the risk of uterine rupture during a subsequent trial of labor.
Am J Obstet Gynecol, Nov. 2000; 183: 1184-6
Objective : The effect of prior vaginal delivery on the risk of uterine rupture in pregnant women undergoing a trial of labor after prior cesarean delivery were examined.
Results : Of 3783 women with 1 prior scar, 1021 (27.0%) also had ³1 prior vaginal delivery. During a subsequent trial of labor, the rate of uterine rupture was 1.1% among pregnant women without prior vaginal delivery and 0.2% among pregnant women with prior vaginal delivery.
Comment : In a logistic regression model that was controlled for potential confounders, previous vaginal delivery was associated with one-fifth the risk of uterine rupture.
Therefore a previous successful VBAC does not eliminate the risk of uterine rupture.
The overall rate of uterine rupture of 0.8% is consistent with rates in other published cohorts.
E L Mozurkewich and E K Hutton (Ann Arbor, Michigan and Toronto, Ontario, Canada)
Elective repeat cesarean delivery versus trial of labor: A meta-analysis of the literature from 1989 to 1999.
Am J Obstet Gynecol, Nov.2000; 183: 1187-97
Results : Fifteen studies with a total of 47,682 women were included.
Conclusion : A trial of labor may result in small increases in the uterine rupture rate and in fetal and neonatal mortality rates with respect to elective repeat cesarean delivery. Maternal morbidity, including febrile morbidity, and the need for transfusion or hysterectomy may be reduced with a trial of labor.
Comment : Between 374 and 809 women would need to undergo elective repeat cesarean delivery to prevent a single case of uterine rupture.
Trial of labor may also result in small increases in fetal and neonatal deaths with respect to elective repeat cesarean delivery. Calculations of the number needed to treat, odds ratios suggest that between 693 and 3332 women would need to undergo elective repeat cesarean delivery to prevent a single fetal or neonatal death attributable to a trial of labor.
A Panting-Kemp, SE. Geller, T.Nguyen et al (Chicago, Illinois)
Maternal deaths in an urban perinatal network, 1992-1998
Am J Obset.Gynecol, Nov. 2000; 183: 1207-12
Objective : The object of this study was to use an in-depth peer-review process to determine the maternal mortality ratio at a single urban perinatal center and to identify factors associated with fatal outcomes to elucidate opportunities for preventive measures to reduce the maternal mortality ratio.
Study Design : Between 1992-1998 all maternal deaths occurring within the perinatal network were identified. A peer-review committee was established to review all available data for each death to determine the underlying cause of death, whether it was related to pregnancy, and whether the death was potentially preventable.
Results : There were 131,500 births and 42 maternal deaths, for a maternal mortality ratio of 31.9 maternal deaths per 100,000 live births. The adjusted pregnancy-related maternal mortality ratio was 22.8 maternal deaths per 100,00 live births, with 375 of those deaths (11/30) deemed potentially preventable and a provider factor cited in >80% of these. Pulmonary embolus and cardiac disease together accounted for 40% of the pregnancy-related deaths.
Conclusion : Local maternal mortality ratios identified through a peer-review process indicate that the magnitude of the problem is much greater than is recognized through national death certificate data. The high proportion of potentially preventable maternal deaths indicates the need for improvement in both patient and provider education.
M.Fitzpatrick, M Behan, P.R. OConnell and C OHerlihy. (Dublin, Ireland)
A randomized clinical trial comparing primary overlap with approximation repair of third-degree obstetric tears.
Am J Obstet Gynecol, Nov.2000; 182: 1220-4
Objective : Authors compared, in a prospective, randomized clinical trial, the subjective and objective outcomes after primary anal sphincter overlap or approximation repair of third degree obstetric tears.
Study Design : In a prospective, randomized clinical trial, 112 primiparous women were studied, who sustained a third-degree tear during a 1-year period (July 1998-June 1999); they were randomly selected, at diagnosis, to receive either an overlap or an approximation repair. Obstetric personnel, trained in both methods, carried out the repairs immediately after delivery. Fifty-five women underwent an overlap procedure, and 57 women underwent an approximation repair. Outcome measures assessed were symptoms of fecal incontinence, abnormal findings on anal manometry, and abnormal findings of endoanal ultrasonography at 3 months post-partum.
Conclusion : The outcome after primary repair of third-degree obstetric tear was similar whether an approximation or an overlap technique was used. Overall symptomatic outcome was good, although two thirds of women had ultrasonographic evidence of residual anal sphincter damage irrespective of the method of repair.
A Dilley, H Austin. M. El-Jamil, W Craig Hooper et al (Atlanta, Georgia and New Brunswick, New Jersey)
Genetic factors associated with thrombosis in pregnancy in a United States population.
Am J Obstet Gynecol, Nov.2000; 183: 1271-7
Objective : Polymorphisms in the genes for factor V (factor V Leiden), prothrombin, methylenetetrahydrofolate reducatse, and angiotensin-converting enzyme have been associated with the occurrence of venous thrombosis. The objective of this study was to determine the relationships of these polymorphisms to thrombosis during pregnancy.
Study Design : This case-control study included 41 case patients with venous thrombosis during pregnancy and 76 control subjects matched for hospital and for race (white vs black) who had a normal pregnancy.
Conclusion : Women who had thrombotic complications during pregnancy demonstrated an increased prevalence of genetic mutations related to coagulation. The additional risk of thrombosis during pregnancy associated with such genetic mutations can be substantial.
M.E.A.Spaanderman, C. Willekes, A.P.G.Hoeks, et al (Maastricht, The Netherlands)
The effect of pregnancy on the compliance of large arteries and veins in healthy parous control subjects and women with a history of preeclampsia.
Am J Obstet Gynecol, Nov.2000; 183: 1278-86
Objective : Early pregnancy is characterized by a fall in total peripheral vascular resistance. In this study, the hypothesis that this phe nomenon is accompanied by rising compliances of the large arteries and veins were studied.
Study Design : In 42 women with a history of preeclampsia and 10 healthy parous control subjects, the following variables in the midfollicular phase and the midluteal phase during the menstrual cycle and again at 5 and at 7 weeks of amenorrhoea: cardiac output, mean arterial pressure, carotid and femoral artery compliances, and venous compliance. The total peripheral vascular resistance was determined as the ratio of mean arterial pressure and cardiac output.
After screening for thrombophilia and hypertension, women with a history of preeclampsia were divided into subgroups with hypertension, thrombophilic disorders, and no underlying abnormalities.
Conclusions : These data support the concept that during normal pregnancy the fall in total peripheral vascular resistance is paralleled by improved macrovascular compliance. The latter adaptive change did not occur in women with a history of preeclampsia with hypertension or without an underlying disorder.
R Gonen, D Bader and M Ajami (Haifa, Israel)
Effects of a policy of elective cesarean delivery in cases of suspected fetal macrosomia on the incidence of brachial plexus injury and the rate of cesarean delivery
Am J Obstet Gynecol, Nov.2000; 183: 1296-300
Objective : The aim of this study was to examine the effects of a policy of elective cesarean delivery for suspected fetal macrosomia on the incidence of brachial palsy and on the cesarean delivery rate.
Study Design : Authors performed a retrospective assessment of a policy that recommends cesarean delivery for macrosomia (fetal weight ³4500g). Fetal weight was estimated by palpation, and ultrasonographic weight estimation was carried out whenever macrosomia was suspected.
Results : During the 4 years of the study 16,416 deliveries resulted in 133 infants with macrosomia (0.8%). Macrosomia was suspected in 47 cases and confirmed by birth weight in 21 (45%). Antenatal estimation of fetal weight was carried out for 115 of the fetuses with macrosomia (86%). Macrosomia was correctly predicted in 21 of 115 cases (18.3%). Thirteen infants with undiagnosed macrosomia were delivered by emergency cesarean procedures, and 99 were delivered vaginally. Three infants with macrosomia (3%) and 14 infants without macrosomia (0.1%) sustained brachial plexus injury. Our policy prevented at most a single case of brachial palsy, and it contributed 0.16% to our cesarean delivery rate.
Conclusions : A policy of elective cesarean delivery in cases of suspected fetal macrosomia had an insignificant effect on the incidence of brachial plexus injury. Its contribution to the rate of cesarean delivery was also small.
N S Weiss, M A Rossing
Oestrogen-replacement therapy and risk of ovarian cancer
The Lancet, vol.358, August 11, 2001,p438
Data presented in the American Cancer Society’s Cancer Prevention Study II, has clearly demonstrated that there is an increase risk of ovarian cancer after HRT and the increased risk remains for atleast 4 years after hormone has been discontinued. Secondly this increased risk of ovarian cancer becomes more important after HRT has been used for 10 years.
The data on increased risk of ovarian cancer by using oestrogen progestagen combination therapy is at present an unknown factor and we may have to wait for 10 years for clarification.
P D Darney (Dept. of Obs.& Gyn. San Francisco, USA)
Misoprostol: a boon to safe motherhood or not ?
The Lancet, vol.358, Sept.1, 2001; p.682
Misoprostol, a heat-stable, orally active prostaglandin E1 analogue has not yet been marketed for post-partum bleeding.
In more than 200 studies, it has been shown to have various uses from elective abortion to cervical priming for delivery or intrauterine procedures, for induction of labour and to control post-partum haemorrhage.
It is not as effective as oxytocin for prophylaxis of postpartum haemorrhage. But the advantage is that while oxytocin needs to be given by injection making it suitable for hospital use, misoprostol is effective orally as a pill and is therefore suitable for use not only in hospital but even at homes.
Editorial Management of anticoagulants during pregnancy
Heart 2001; 86: 125-126
Under normal circumstances even though there is hypercoagulability during normal pregnancy, the thromboembolic risks are minor. However the presence of valvular defects in atrial fibrillation, mechanical prosthesis or in coagulation anomaly, there can be serious risks. Anticoagulant is recommended.
Unfortunately, heparin protects the fetus and aggravates maternal risk while oral anti-coagulants protect the mother and aggravate fetal risk.
The addition of low dose of aspirin has been advocated.
A possible molecular explanation for pre-eclampsia.
Lancet, vol.357, 9 June 2001, pg.1857
Pre-eclampsia could be caused by decreased availability of nitric oxide (NO). NO is a major mediator of blood vessel relaxation. It is either used immediately after production or is bound to albumin, forming S-nitroso albumin. Researchers from Univ. of Pittsburgh (Circulation Res. 2001; 88, 1210-15) have shown that women with pre-eclampsia have significantly higher levels of S-nitroso albumin in their blood. This is consistent with the hypothesis that NO is being stored in the blood and is not being released in large enough quantities to maintain a healthy blood flow, leading to profound vasoconstriciton throughout the womans body.
Since ascorbate is essential for the decomposition of S-nitorsothiols to release NO, the authors speculate that vitamin C deficiency that is usually associated with pre-eclampsia may result in less NO released from its protein-bound store in the blood.
Future clinical studies will be necessary to test whether antioxidant vitamins like C are able to reduce the incidence of pre-eclampsia.
How P53 is inactivated following DNA damage.
Lancet, vol.357, June 9, 2001, pg.1857
Activation of P53, which occurs in response to DNA damage, suppresses tumour growth by preventing abnormal cells from proliferating and by activating the apoptosis pathway.
P53 should not function during normal cell growth under conditions of no DNA damage. So, the cell exports P53 from the nucleus to the cytoplasm for degradation.
Phosphorylation of Ser-15 after DNA damage inhibits the function of the export signal thereby blocking P53 export and its subsequent degradation in cytoplasm.
As the wildtype of P53 gene is still present in half of all tumours, these findings point to a new target for development of drugs to reactivate P53 in patients. By blocking export of P53, we might be able to reactivate P53 function in tumours to either block cell proliferation or induce apoptosis.
D Hubacher, R Lara-Ricalde, D J Taylor et al
Use of Copper Intrauterine Devices and The Risk of Tubal Infertility among Nulligravid Women.
N. Eng.Jr. Med., vol. 345, No.8, Aug.23, 2001, p.561-7
P. D. Darney (Univ. of California, San Francisco)
Time to Pardon the IUD.
N Eng.J Med. Vol.345, No.8, Aug.23, 2001, p.608
Intrauterine device (IUD) has been used for years as contraceptive device. They can be made of either copper or plastic. Their main drawbacks of IUDs are local infection, inflammation and permanent infertility.
A survey conducted showed that the copper IUDs do not carry the risk of permanent infertility but the plastic ones do.
D C G Skegg
Commentary – Hormone Therapy and Heart Disease After the Menopause
American Heart Association Recommendations on HRT and CVD
The Lancet October 13, 2001, Vol.358 (9289) Pg. 1196-1197
HRT should not be initiated for the secondary prevention of CVD.
Firm clinical recommendations for primary prevention await the results of ongoing randomised clinical trials.
There are insufficient data to suggest that HRT should be initiated for the sole purpose of primary prevention of CVD.
Initiation and continuation of HRT should be based on established noncoronary benefits and risks, possible coronary benefits.
R J Norman
Commentary – Reproductive Consequences of COX-2 Inhibition
The Lancet October 20, 2001, Vol.358 (9290) Pg. 1287-1288
Many reproductive processes-eg, ovulation, fertilisation, implantation, decidualisation, and parturition – depend on prostaglandin ligand-receptor interactions.
In experimental mice NSAIDs have been shown to induce infertility because of interference with reproductive processes.
There are many human case reports that infertility is produced by NSAIDs and COX-1/COX-2 inhibitors. However, fertility is restored by discontinuing these drugs. Women attempting to become pregnant should avoid taking these drugs.
W J Ott, and K Taysi (St. Louis, Missouri)
Obstetric ultrasonographic findings and fetal chromosomal abnormalities: Refining the association.
Am J Obstet Gynecol; June 2001; 184: 1414-21
Objective : In an attempt to refine the role of ultrasonography in screening and identifying fetuses at risk for chromosomal abnormalities, a retrospective review of patients undergoing genetic amniocentesis was undertaken.
Study Design : Computer databases from the perinatal biology laboratory and cytogenetics laboratory were correlated to compare the results of the fetus’ ultrasonographic examination with the cytogenetic results from amniocentesis. Univariate and multivariate analysis were used to determine the best correlations between ultrasonographic findings and chromosomal abnormalities (study 1). The results were used to construct regression analysis formulas and a Neural Network program to predict the presence or absence of chromosomal abnormalities in a second set of patients undergoing genetic amniocentesis.
Results : One hundred twenty-five chromosomal abnormalities were found in 3775 fetuses in study 1 (3.3%). Multivariate analysis showed significant correlations between anomalies of the central nervous system, heart, face and neck, and extremities and increased nuchal fold, increased bowel echogenicity, abnormal biparietal diameter-to-femur ratio, and the presence of chromosomal abnormalities. Regression equations and a Neural Network program successfully predicted the presence or absence of fetal chromosomal abnormalities in a second set of 910 at- risk fetuses.
Conclusion : A normal ultrasonographic examination result in patients who are at increased risk for fetal chromosomal abnormalities reduces the risk 2-to-3-fold, whereas the presence of any major ultrasonographic abnormality or certain minor abnormalities significantly increases the risk. The application of these results to low-risk patients is still premature.
S. C. Blackwell, J. Moldenhauer, S. S. Hassan, M. E. Redman, J. S. Refuerzo, S. M. Berry, and Y. Sorokin (Detroit, Michigan)
Meconium Aspiration Syndrome in Term Neonates with Normal Acid-Base Status at Delivery: Is it Different?
Am J Obstet Gynecol; June 2001; 184: 1422-26
Objective : The authors’ aim was to compare the clinical characteristics of meconium aspiration syndrome in cases with pH ³ 7.20 and in those with pH < 7.20.
Study Design : Medical records of diagnostic codes from the International Classification of Diseases, Ninth Revision, were used to identify neonates with severe meconium aspiration syndrome who had been delivered at the authors’ institution from 1994 through 1998. Severe meconium aspiration syndrome was defined as a mechanical ventilator requirement of > 48 hours. Clinical data including neonatal outcomes of cases of meconium aspiration syndrome associated with umbilical pH ³ 7.20 at delivery were compared with data on outcomes of cases with pH < 7.20.
Results : During this 4-year study period, 4985 singleton term neonates were delivered through meconium-stained amniotic fluid. Forty-eight cases met all study criteria, and pH values at delivery were as follows: pH ³ 7.20, n = 29, and pH < 7.20, n = 19. There were no differences between groups in the incidence of clinical chorioamnionitis, in the presence of meconium below the vocal cords, or in birth weight. Neonates with meconium aspiration syndrome and umbilical pH ³ 7.20 at delivery developed seizures as often as those with pH < 7.20 (20.1% vs 21.1%; P = 1.0).
Conclusion : Normal acid-base status at delivery is present in many cases of severe meconium aspiration syndrome, which suggests that either a preexisting injury or a nonhypoxic mechanism is often involved.
Comment : There are possible medicolegal implications to our findings. Intrapartum mismanagement is often alleged in meconium aspiration syndrome. Normal acid-base status at delivery, even in cases with associated neurologic injury, suggests that either a preexisting injury or a nonhypoxic mechanism, rather than an intrapartum event, is involved in many cases of meconium aspiration syndrome.
N. A. Ginsberg, and C. Moisidis (Chicago, Illinois)
How To Predict Recurrent Shoulder Dystocia
Am J Obstet Gynecol; June 2001; 184: 1427-30
Objective : The authors’ aim was to determine the rate and risk factors for recurrent shoulder dystocia.
Study Design : A retrospective analysis of patients diagnosed with shoulder dystocia was performed by searching a computerized database from January 1, 1993, to June 30, 1999 for the following information:
(1) vaginal deliveries, either spontaneous or operative, (2) shoulder dystocia, (3) birth weight, (4) duration of second stage of labor, (5) parity, and (6) gestational diabetes. Statistical analyses included c2 and t test.
Results : There were 39,681 vaginal deliveries with 602 (1.5%) complicated by shoulder dystocia. Sixty-six patients underwent a subsequent vaginal delivery, and 11 (16.7%) experienced another shoulder dystocia.
The odds ratio for a recurrent shoulder dystocia was 10.98 (P < .000001). Nine of the 11 patients with recurrent shoulder dystocia compared with 28 of 55 without a recurrence were nulliparous women in their index pregnacy (P < .001). The mean fetal weights were 3885 g in the recurrent dystocia group and 3702 g in the group without recurrences (P < .03). Gestational age, operative delivery, and gestational diabetes were similar in the two groups.
Conclusion : Factors that appear to increase the recurrence risk of shoulder dystocia include fetal weight and maternal parity. Prior shoulder dystocia is the single greatest predictive factor.
A. C. Sciscione, T. Zainia, T. Leet, J. N. Winn, and H. N. Winn (Newark, Delaware, and St. Louis, Missouri)
A New Device for Measuring Intrauterine Temperature
Am J Obstet Gynecol; June 2001; 184: 1431-35
Objective : The authors’ evaluated a new device that uses the intrauterine pressure catheter to measure the maternal temperature in patients who are in labor.
Study Design : The study was conducted at two medical centers, Christiana Hospital in Newark, Delaware, and Saint Louis University/St Mary’s Health Center in St Louis, Missouri, from September 1, 1997, to May 2, 1998. An intrauterine pressure catheter with a thermistor sensor in the tip was placed into the uterus after spontaneous rupture of membranes. The intrauterine, oral, and tympanic temperatures were simultaneously obtained immediately after insertion of the intrauterine pressure catheter and then hourly until delivery or the initiation of amnioinfusion.
Results : The study comprised 97 patients and 404 temperature readings with a temperature range of 34.70 C to 40.70 C. The normal mean ± SD for the oral, tympanic, and intrauterine temperatures was 36.70 C ± 0.50 C, 36.80 C ± 0.50 C, and 37.30 C ±0.40 C, respectively. There was a linear relationship among the oral, tympanic, and intrauterine temperatures. All three methods showed a significant increase in mean body temperature after epidural anesthesia.
Conclusion : The new device, the intrauterine pressure-temperature catheter, provides a convenient and accurate means of continuously measuring uterine temperature in patients who are in labor and require intrauterine monitoring.
Catherine Vasilakis-Scaramozza, Hershel Jick
Risk of Venous Thromboembolism With Cyproterone or Levonorgestrel Contraceptives
Lancet, Vol.358, October 27, 2001, Pg. 1427-29
Summary: Results of several small studies have shown that there is an excess risk of venous thromboembolism in users of oral contraceptives containing cyproterone compared with those containing levonorgestrel.
The authors conducted a case-control study and the results suggest that risk of venous thromboembolism is increased 4 fold in women taking contraceptives containing cyproterone by comparison with those exposed to levonorgestrel.
Contraceptives containing cyproterone are often prescribed for women with a history of hirsutism and acne.
A. Aberg, H. Rydhstroem and A. Frid (Lund and Helsingborg, Sweden)
Impaired Glucose Tolerance Associated With Adverse Pregnancy Outcome: A Population-Based Study In Southern Sweden
Am J Obstet Gynecol Jan. 2001; 184: 77-83
Objective : A population-based study of maternal and neonatal characteristics and delivery complications in relation to the outcome of a 75-g, 2-hour oral glucose tolerance test at 25 to 30 weeks gestation.
Study Design : An oral glucose tolerance test was offered to pregnant women in a geographically defined population. Pregnancy outcome was analyzed according to the test result.
Results : Among women delivered at Lund Hospital, 4526 women were identified with an oral glucose tolerance value of < 7.8 mmol/L (< 140 mg/dL), 131 women with a value of 7.8 to 8.9 mmol/L (140-162 mg/dL), and 116 women with gestational diabetes (³ 9.0 mmol/L [³ 162 mg/dL]). A further 28 cases of gestational diabetes were identified, giving a prevalence of 1.2%. An increased rate of cesarean delivery and infant macrosomia was observed in the group with a glucose tolerance value of 7.8 to 8.9 mmol/L (140-162 mg/dL) and in the gestational diabetes group. Advanced maternal age and high body mass index were risk factors for increased oral glucose tolerance values in 12,657 screened women in the area.
Conclusion : The study stresses the significance of moderately increased oral glucose tolerance values.
S. Liu, S. W. Wen, K. Demissie, S. Marcoux, and M. S. Kramer (Ottawa, Ontario, and Sainte-Foy and Montreal Quebec, Canada, and Piscataway, New Jersey)
Maternal Asthma and Pregnancy Outcomes: A Retrospective Cohort Study
Am J Obstet Gynecol Jan. 2001; 184: 90-6
Objective : The relationship between asthma during pregnancy and selected infant and maternal outcomes was examined.
Study Design : A retrospective cohort study was conducted on mother-infant dyads identified from a linked infant and maternal hospital discharge database in the Canadian province of Quebec between fiscal years 1991-1992 and 1995-1996. Mothers with asthma (n=2193) were compared with a randomly selected control sample (n=8772) from the remaining population of mothers.
Results : After important confounding variables were accounted for, maternal asthma was significantly associated with several adverse infant outcomes, including preterm birth and birth of infants who are very small for gestational age, and adverse maternal outcomes, such as idiopathic preterm labor, early idiopathic preterm labor, preeclampsia, transient hypertension of pregnancy, pregnancy-associated hypertension, chorioamnionitis, and cesarean delivery.
Conclusion : Results demonstrated that pregnant women with asthma are at substantially increased risk for several adverse infant and maternal outcomes and suggest the need for extra attention to mothers with asthma and their infants.
M. I. Evans, R. L. Berkowitz, R. J. Wapner, R. J. Carpenter, J. D. Goldberg, M. A. Ayoub, J. Horenstein, M. Dommergues, B. Brambati, K. H. Nicolaides, W. Holzgreve, and I. E. Timor-Tritsch (Philadelphia, Pennsylvania, Detroit, Michigan, New York, New York, Houston, Texas, San Francisco, and Los Angeles, California, Paris, France, Milan, Italy, London, United Kingdom, and Basel, Switzerland)
Improvement in Outcomes of Multifetal Pregnancy Reduction with Increased Experience
Am J Obstet Gynecol Jan. 2001; 184: 97-103
Objective : This study was undertaken to evaluate a decade of data on multifetal pregnancy reductions at centers with extensive experiences.
Study Design : A total of 3513 completed cases from 11 centers in 5 countries were analyzed according to year (before 1990, 1991-1994, and 1995-1998), starting and finishing numbers of embryos or fetuses, and outcomes.
Conclusion : Multifetal pregnancy reduction outcomes at the authors centers for both losses and early prematurity have improved considerably with experience. Reductions from triplets to twins and now from quadruplets to twins carry outcomes as good as those of unreduced twin gestations. Patient demographic characteristics continues to change as more older women use assisted reproductive technologies. In terms of losses, prematurity, and growth, higher starting numbers carry worse outcomes.
Comments : The data on finishing numbers confirm that reduction to twins carries the lowest loss rate, although the gap with singletons has decreased considerably from older data.
D. R. Danilenko-Dixon, J. A. Heit, M. D. Silverstein, B. P. Yawn, T. M. Petterson, C. M. Lohse, and L. J. Melton (Rochester, Minnesota, and Charleston, South Carolina)
Risk Factors for Deep Vein Thrombosis and Pulmonary Embolism During Pregnancy Or Post Partum: A Population-Based, Case-Control Study
Am J Obstet Gynecol Jan. 2001; 184: 104-10
Objective : The authors sought to determine the risk factors for deep vein thrombosis and pulmonary embolism during pregnancy or post partum.
Study Design : A population-based case-control study was performed. All Olmsted County, Minnesota, residents with a first lifetime deep vein thrombosis or pulmonary embolism during pregnancy or post partum from 1996 to 1990 were identified (N=90).
Where possible, a resident without deep vein thrombosis or pulmonary embolism was matched to each patient by date of the first live birth after the patients child. The medical records of all remaining patients and all control subjects were reviewed for > 25 baseline characteristics, which were tested as risk factors for deep vein thrombosis or pulmonary embolism.
Results : In multivariate analysis smoking (odds ratio, 2.4) and prior superficial vein thrombosis (odds ratio, 9.4) were independent risk factors for deep vein thrombosis or pulmonary thrombosis during pregnancy or post partum.
Conclusion : Venous thromboembolism prophylaxis may be warranted for pregnant women with prior superficial vein thrombosis. Smoking cessation should be recommended, especially during pregnancy and the postpartum period.
Comments : Tobacco smoking, prior superficial vein thrombosis and varicose veins were significant univariate risk factors. The risk of venous thromboembolism is higher during the puerperium compared with during pregnancy.
Potential limitations of this study, is that during the early years noninvasive diagnostic tests for deep vein thrombosis and pulmonary embolism (eg, impedance, plethysmography, compression duplex ultrasonography, ventilation-perfusion lung scan) were unavailable.
Postpartum women with manual delivery of the placenta or postpartum hemorrhage and possibly women with premature delivery or a requirement for transfusion therapy during or after delivery should have careful clinical observation for postpartum venous thromboembolism.
T. Jansson, Y. Ekstrand, M. Wennergren, and T. L. Powell (Goteborg, Sweden)
Placental Glucose Transport in Gestational Diabetes Mellitus
Am J Obstet Gynecol Jan. 2001; 184: 111-6
Objective : It has been previously reported that type 1 diabetes mellitus with hyperglycemia during the first trimester is associated with an up-regulation of placental glucose transport at term. It was speculated that glucose concentrations regulate placental glucose transporters only during early pregnancy. To test this hypothesis the authors studied placental glucose transport in gestational diabetes mellitus, which is associated with hyperglycemia mainly during the second half of pregnancy.
Study Design : Syncytiotrophoblast microvillous membrane vesicles and basal membrane vesicles were isolated from uneventful pregnancies (control group, n=32) and pregnancies complicated by gestational diabetes mellitus (n=18). Glucose uptake and glucose transporter1expression were studied by means of radiolabeled tracers and Western blotting, respectively.
Conclusion : These findings are consistent with the hypothesis that the sensitivity of placental glucose transporters to regulation by nutrient availability is limited to early pregnancy.
H.L. Hedriana, C. J. Munro, E. M. Eby-Wilkens, B. L. Lasley (Davis, California)
Changes in Rates of Salivary Estriol Increases Before Parturition At Term
Am J Obstet Gynecol Jan. 2001; 184: 123-30
Objective : The aim of this study was to characterize the increases of salivary estriol concentrations before the onset of labor at term.
Study Design : Salivary estriol concentrations were measured in weekly patient-collected samples by means of a sensitive (mean ± SD threshold, 0.025 ± 0.001 ng/mL; coefficient of variation, 3.8%) direct enzyme immunoassay in a microtiter plate format. The salivary estriol concentrations in 16 healthy pregnant women were characterized from 30 weeks gestation until the time of parturition and delivery. Samples were stored frozen at collection and analyzed in batches after delivery.
Conclusion : These data demonstrate in normal pregnancies
(1) that a direct, nonradiometric measure of salivary estriol concentration can be used to monitor the late pregnancy increase in estriol production,
(2) that 35 weeks gestation marks a positive inflection point of the onset of increased estriol production, and
(3) that the late pregnancy rise in salivary estriol concentration shows distinct patterns that tend to be characteristic of the length of pregnancy. These data support the concept that the rate of increase of estriol production is related to the timing of the onset of labor.
Comments : Observations suggested that the rate of estriol production, rather than the absolute concentration, might be more predictive of impending labor and delivery.
The median salivary estriol concentration values plateaued at 37 weeks gestation in those subjects who had labor induced after 40 weeks gestation for common obstetric indications.
When used as an aid to assess the likelihood of preterm labor and delivery, an increase in estriol production was demonstrated 3 to 4 weeks before delivery in a heterogeneous population from multiple medical centers.
With an optimal salivary estriol concentration cutoff value of 2.3 ng/mL between 22 and 36 weeks gestation. If the test result was negative (salivary estriol concentration <2.3 ng/mL), there was a 95% likelihood that delivery would not occur within 2 to 3 weeks.
Improvement in prediction of preterm births could possibly be obtained by determining the rate of salivary estriol concentration production across gestational week intervals after correct identification of the baseline levels.
J. E. Harding, J-M Pang, D. B. Knight, and G. C. Liggins (Auckland, New Zealand)
Do Antenatal Corticosteroids Help in the Setting of Preterm Rupture of Membranes?
Am J Obstet Gynecol Jan. 2001; 184: 131-9
Objective : It is now accepted that corticosteroid administration before preterm delivery reduces neonatal mortality and morbidity. However, corticosteroid use in the setting of rupture of membranes remains controversial.
Study Design : Data from the first and largest randomized trial was reviewed and included in a new meta-analysis.
Results: Data from 318 women with rupture of membranes in the Auckland Trial showed that there was a trend toward reduction of the risk of respiratory distress syndrome with corticosteroids but that this trend did not reach statistical significance. There was little effect on the risks of neonatal death, intraventricular hemorrhage, and fetal, neonatal, or maternal infection.
Combined data from 15 controlled trials involving >1400 women with rupture of membranes confirmed that corticosteroids reduce the risks of respiratory distress syndrome (relative risk, 0.56; 95% confidence interval, 0.46-0.70), intraventricular hemorrhage (relative risk, 0.47; 95% confidence interval, 0.31-0.70) and necrotizing enterocolitis (relative risk, 0.21; 95% confidence interval, 0.05-0.82). They also may reduce the risk of neonatal death (relative risk, 0.68; 95% confidence interval, 0.43-1.07).
They do not appear to increase the risk of infection in either mother (relative risk, 0.86; 95% confidence interval, 0.61-1.20) or baby (relative risk, 1.05; 95% confidence interval, 0.66-1.68). The duration of rupture of membranes does not alter these outcomes.
Conclusion : The available data indicate that corticosteroid administration is beneficial in the setting of rupture of membranes. In the authors opinion further trials to address this question cannot be justified.
Comments : The greatest concerns regarding the use of antenatal corticosteroids in women with rupture of membranes have centered around the risks of infection for mother and baby. Previous systematic reviews have suggested that there is no increase in the risk of fetal and neonatal infection, but the estimates have been imprecise, and a moderate effect would not have been evident.
L. Mandelbrot, G. Peytavin, G. Firtion, and R. Farinotti (Paris, France)
Maternal-Fetal Transfer and Amniotic Fluid Accumulation of Lamivudine in Human Immunodeficiency Virus-Infected Pregnant Women
Am J Obstet Gynecol Jan. 2001; 184: 153-8
Objective : The purpose of this study was to investigate placental transfer and amniotic fluid concentrations of lamivudine in human immunodeficiency virus-infected women who received the agent during pregnancy.
Study Design : Mothers in the study were receiving antiretroviral therapy that included lamivudine in a clinical setting. Maternal blood, cord blood, and amniotic fluid samples were obtained simultaneously at the time of delivery from 57 mother-infant pairs.
Results : At a median of 8.5 hours after the last maternal oral 150-mg dose of lamivudine, median maternal and fetal plasma concentrations were 302 and 240 ng/mL, respectively. Individual maternal and fetal concentrations were strongly correlated (r2 = 0.36; P < 10-4), and their median ratio was about 1. The median concentration in the amniotic fluid was 5 times higher than that in maternal plasma (upper range of ratio, 133).
Conclusion : Lamivudine appeared to cross the placenta by simple diffusion and is concentrated in the amniotic fluid. High amniotic fluid levels of lamivudine may carry both benefits and risks for the child.