Faculty Bibliography

OBJECTIVE:The purpose of this study was to evaluate temporal trends in abruption risk and to assess how much underlying changes in the clinical determinants may have affected these trends. STUDY DESIGN/METHODS:We used the National Hospital Discharge Summary data (1979-2001), an annual survey of sampled non-federal, short stay, general, and specialty hospitals in the United States. Trends in abruption were assessed for the periods 1979 through 1981 and 1999 through 2001. Clinical determinants of abruption that were evaluated included hypertensive diseases, anemia, gestational diabetes mellitus, preterm labor, preterm premature rupture of membranes, chorioamnionitis, oligohydramnios, obstetric shock/trauma, uterine tumors, short umbilical cord, and velamentous cord insertion. Temporal trends in abruption were examined before and after adjustment for determinants through multivariable logistic regression. RESULTS:The rate of abruption increased 92% (95% CI, 88, 96) among black women between 1979-1981 (0.76%; n = 13,584 women) and 1999-2001 (1.43%; n = 18,960 women). Among white women, the rate increased by 15% (95% CI, 14,16) over the same period, from 0.82% (n = 66,186 women) in 1979-1981 to 0.94% (n = 59,284 women) in 1999-2001. The determinants that were associated with trends in abruption included anemia, gestational diabetes mellitus, preterm labor, short umbilical cord, and velamentous cord insertion, although their effects varied substantially by maternal race. CONCLUSION/CONCLUSIONS:The temporal increase in rates of abruption may reflect a true increase in risk or may be the result of improved diagnosis of both abruption and its determinants. Although the cause of abruption is still speculative, the trend is of concern and deserves scrutiny.

OBJECTIVE:The purpose of this study was to examine if neonatal mortality rates (NMR) based on birth weight discordance (BWD) differ based on mode of delivery. STUDY DESIGN/METHODS:The population-based US "matched multiple birth" database (1995 to 1998) was used to examine the effect of vaginal/vaginal (VV) and cesarean/cesarean (CC) modes of delivery (MOD) on neonatal mortality (<28 days after birth). Births at <32 weeks, congenital malformations, chromosomal anomalies, and discordant MOD (vaginal/cesarean) were excluded. The association between MOD (with CC as the reference) and neonatal mortality was expressed as relative risks (RR) with 95% CI, derived from logistic regression models. RESULTS:The NMR increased with increasing degrees of BWD regardless of mode of delivery. CC was associated with decreased NMR when BWD was between 20% and 40%, but this reached significance at BWD > or =40%; VV pairs had a 1.6-fold (95% CI 1.1-2.2) increased NMR compared with CC. CONCLUSION/CONCLUSIONS:In twins with BWD <40%, MOD has no effect on NMR. Beyond or equal to 40% discordance, there was lower NMR with cesarean-cesarean delivery.

OBJECTIVE:To estimate the pattern of maternal vascular reactivity in normal and high-risk pregnancies using postocclusion brachial artery diameter. METHODS:Prospective, longitudinal study of 44 low-risk singleton pregnancies and 28 high-risk pregnancies, defined as pregestational diabetes (n = 7), chronic hypertension (n = 4), twin gestation (n = 6), and a previous history of preeclampsia, fetal growth restriction, or vascular disease (n = 11). During each trimester, the brachial artery was ultrasonographically imaged above the antecubital crease. Brachial artery diameter was measured and then occluded for 5 minutes using an inflated blood pressure cuff. Changes in brachial artery diameter at 1 minute after occlusion were expressed as percent change from baseline and were compared across trimesters for both low-risk and high-risk groups, adjusting for potential confounders. RESULTS:Brachial artery diameters were increased after occlusion in every trimester for all groups. For low-risk women, the degree of postocclusion brachial artery dilatation was similar in the first and second trimesters, but was lower in the third trimester. In the first trimester, low-risk women had significantly greater brachial artery diameter increases at 1 minute compared with high-risk singleton pregnancies (19% compared with 12%; P <.001). Compared with low-risk women, pregnancies complicated by pregestational diabetes or chronic hypertension had significantly smaller 1-minute brachial artery diameter changes in the first trimester (7.0 +/- 0.5%, P <.001), whereas twin gestations had greater brachial artery responses (22.9 +/- 6.0%, P <.001). Women with previous preeclampsia or vascular disease had responses similar to low-risk women. CONCLUSION/CONCLUSIONS:Maternal vascular reactivity as assessed by postocclusion brachial artery dilatation decreases in the third trimester in both low-risk and high-risk women. In addition, singleton pregnancies at high risk for preeclampsia display decreased brachial artery reactivity compared with low-risk women.

Dystocia, or slow labor, is the leading cause of first-time cesarean sections. Current diagnostic guidelines for dystocia are vague, and there is no clear postoperative confirmatory evidence to assess the correctness of this diagnosis. For several decades, various professional organizations have indicated that cesarean rates could be lowered safely and have recommended levels that are far below national averages. The three major factors, of roughly equal importance, associated with cesarean for slow labor are the baby's weight, the mother's height, and the threshold at which the physician believes it is reasonable to intervene. The last is the only modifiable factor, and quality programs are a major part of changing medical behavior. By using two study designs, the effect of a mathematical method for evaluating labor progress on the rate of cesarean section was measured. In the prospective randomized clinical trial, the relative risk of cesarean in the experimental group was unchanged at 1.04. In the pretest-posttest analysis, the rates fell from 19.54% to 17.04% at 6 months and 16.62% at 12 months.

OBJECTIVE:To examine whether preterm premature rupture of membranes (PROM), intrauterine infection, and oligohydramnios are risk factors for placental abruption. METHODS:Data for this retrospective cohort study were derived from the 1988 National Maternal and Infant Health Survey (N = 11,777). Association between abruption and these clinical risk factors was expressed as relative risk (RR) and 95% confidence interval (CI), with multivariate adjustment for potential confounders. RESULTS:The overall incidence of abruption was 0.87%. The risk of abruption was 3.58-fold higher (95% CI 1.74-7.39) among women with preterm PROM (2.29%) compared with women with intact membranes (0.86%). The rates of abruption among women with and without intrauterine infection were 4.81% and 0.83%, respectively (RR 9.71, 95% CI 3.23-29.17). However, oligohydramnios was not associated with abruption (1.46% compared with 0.87%; RR 2.09, 95% CI 0.92-5.31). Compared with women with intact membranes, the RR for abruption among preterm PROM and whose membranes were ruptured for 24-47 hours and 48 hours or more before delivery, respectively, were 2.37 (95% CI 0.99-9.09), and 9.87 (95% CI 3.57-27.82). When preterm PROM was accompanied by intrauterine infections, the RR for abruption was 9.03 (95% CI 2.80-29.15) compared with women with intact membranes and no infections. Similarly, preterm PROM accompanied by oligohydramnios conferred over a 7.17-fold risk (95% CI 1.35-38.10) for abruption compared with women with neither of these 2 conditions. CONCLUSION/CONCLUSIONS:Women presenting with preterm PROM are at increased risk of developing abruption, with the risk being higher either in the presence of intrauterine infections or oligohydramnios. Physicians managing patients with preterm PROM should be aware that these patients are at increased risk of developing abruption after 24 hours following preterm PROM.

OBJECTIVE:To determine the magnitude of risk for fetal death among singleton pregnancies in relation to maternal age, and to compare the risks with other common indications for fetal testing. STUDY DESIGN/METHODS:We performed a retrospective cohort analysis of singleton births delivered between 1995 and 2000 using the US linked birth/infant death data. Gestational age at < 24 weeks and fetuses with anomalies were excluded. Fetal death rates at > or = 24 and > or = 32 weeks were calculated among women aged 15-19, 20-24, 25-29, 30-34, 35-39, 40-44 and 45-49 years, as well as for other common indications for testing: chronic and pregnancy-induced hypertension, diabetes and small-for-gestational age (SGA). The association between maternal age and fetal deaths was derived after adjusting for potential confounders through multivariable logistic regression models. Relative risks (RR) and 95% confidence intervals (CI) were derived from these models after adjusting for the effects of gravidity, race, marital status, prenatal care, education, smoking and placental abruption. RESULTS:Among the 21,610,873 singleton births delivered at > or = 24 weeks, fetal deaths occurred in 58,580 (2.7 per 1000). Births to young (15-19 years) and older (> or = 35 years) women comprised 12.6% and 11.4%, respectively. Compared with women aged 20-24 years, young women did not experience an increased risk of fetal death. However, increasing rates of fetal death at > or = 24 and at > or = 32 weeks were seen with increasing maternal age. The RR for fetal death at > or = 24 and at > or = 32 weeks among women 35-39 years were 1.21 and 1.31, respectively, while the RRs were 1.62 and 1.67 among women aged 40-44 years. Women 45-49 years were 2.40-fold (95% CI 1.77, 3.27) and 2.38-fold (95% CI 1.64, 3.46) as likely to deliver a stillborn fetus at > or = 24 weeks and > or = 32 weeks, respectively. RRs for fetal death at > or = 24 and > or = 32 weeks for hypertensive disease, diabetes, and SGA ranged between 1.46 and 4.95. CONCLUSION/CONCLUSIONS:Fetal deaths are increased among older women (> or = 35 years). Fetal testing in women of advanced maternal age may be beneficial.

OBJECTIVE:The purpose of this study was to determine the best available antepartum fetal testing methods according to the underlying pathophysiologic condition. STUDY DESIGN/METHODS:We reviewed the current literature and our clinical experience with respect to condition-specific antepartum fetal testing. RESULTS:The efficacy of most antepartum tests that we use today is not supported by randomized controlled clinical trials, but from observational nonrandomized studies and expert opinion (evidence levels II or III). CONCLUSION/CONCLUSIONS:Based on the available evidence, the accuracy of a test depends on the underlying pathophysiologic condition. To improve accuracy, we must use condition-specific fetal testing.

OBJECTIVE:To determine whether differences in the clinical entities of HELLP syndrome and severe preeclampsia are associated with different placental lesions. STUDY DESIGN/METHODS:This was a case control study of singleton pregnancies with HELLP syndrome or severe preeclampsia. Archived pathology slides were retrieved and reviewed. Clinical and histopathological features were compared between the two groups. RESULTS:There were 31 women with HELLP syndrome and 56 with severe preeclampsia. HELLP syndrome was associated with epigastric pain and higher levels of LDH, bilirubin, liver enzymes and fibrin degradation products. Hemoglobin, hematocrit and platelet counts were lower. Abruption lesions of the placenta were less common with HELLP syndrome (Odds Ratio 0.1 95% Confidence Interval 0.01,0.8). None of the other 22 placental features examined were different between the two conditions. CONCLUSION/CONCLUSIONS:The significant overlap between HELLP syndrome and severe preeclampsia for both clinical and placental features suggests that the two conditions represent a spectrum of essentially the same pathophysiologic process.

OBJECTIVE:The purpose of this article was to propose guidelines for the design, execution, interpretation, and reporting of economic evaluation studies in obstetrics. Study design We performed a PubMed search of economic evaluation articles to identify those articles that deal with the quality of published economic evaluation studies, the development of guidelines, and the development of checklists/guidelines for the reporting of economic evaluation studies. All other articles were excluded from the review. RESULTS:We identified 160 articles. We included 8 articles in our review that reported on the quality of published economic analyses, 12 articles that reported on guidelines, and 3 articles that reported on checklists/guidelines that are used by journals. There were 2 articles that dealt with the quality of published economic evaluations in obstetrics and gynecology, both of which showed less than optimal quality. There were only 4 articles that provided some general guidelines for the reporting of economic evaluations in obstetrics and gynecology. We found no articles on any checklist/guidelines for the reporting of economic evaluation studies in obstetrics and gynecology. CONCLUSION/CONCLUSIONS:There is a need to improve the design, execution, interpretation, and reporting of economic evaluation studies in obstetrics.