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Objective: To evaluate whether vaginal flora is altered by antibiotic exposure and associated with a risk of preterm birth, particularly among women with initially normal vaginal flora., Methods: This was a secondary analysis of a randomized trial of metronidazole and erythromycin for the prevention of preterm birth among women with a positive fetal fibronectin test. Vaginal swabs for Nugent Gram stain score were collected for classification of bacterial vaginosis before and after antibiotic exposure and read at a central laboratory. Change in Nugent score was assessed for women with (score 7 or higher) or without (score lower than 7) bacterial vaginosis. Linear regression analysis evaluated whether change in Nugent score was associated with preterm birth., Results: Two hundred women without and 69 women with bacterial vaginosis had Gram stain performed before and after antibiotic therapy. Median Nugent score for all women declined from 4.0 to 2.0 after antibiotic therapy (P<.001). Nugent score declined both for those without (from 2.0 to 1.5, P=.11) and, more dramatically, those with bacterial vaginosis (from 8.0 to 3.0, P<.01). The components of the Nugent score that were affected by antibiotic exposure were similar among women with and without bacterial vaginosis. Antibiotic exposure and the change in Nugent score were unrelated to preterm birth among bacterial vaginosis-negative women., Conclusion: Antibiotic exposure is not associated with preterm birth and does not worsen Nugent score among women with normal vaginal flora and positive fetal fibronectin., Level of Evidence: II.

Objective: To determine whether asthma-specific quality of life during pregnancy is related to asthma exacerbations and to perinatal outcomes., Methods: This was a secondary analysis of data from a randomized controlled trial of inhaled beclomethasone versus theophylline in the treatment of moderate asthma during pregnancy. The Juniper Asthma Quality of Life Questionnaire (AQLQ) was administered to patients at enrollment. Exacerbations were defined as asthma symptoms requiring a hospitalization, unscheduled medical visit, or oral corticosteroid course., Results: Quality of life assessments were provided by 310 of the 385 participants who completed the study. There was more than a 25% decrease in the odds of a subsequent asthma exacerbation for every 1-point increase in AQLQ score for the overall score (odds ratio [OR] 0.73, 95% confidence interval [CI] 0.55-0.96), emotion domain (OR 0.72, 95% CI 0.59-0.88), and symptoms domain (OR 0.73, 95% CI 0.57-0.94). These relationships were not significantly influenced by initial symptom frequency or forced expiratory volume in 1 s (FEV(1)). No significant relationships were demonstrated between enrollment AQLQ scores and preeclampsia, preterm birth, low birth weight, or small for gestational age., Conclusion: Asthma-specific quality of life in early pregnancy is related to subsequent asthma morbidity during pregnancy but not to perinatal outcomes.

Objective: To estimate whether maternal carriage of the prothrombin gene G20210A mutation is associated with pregnancy loss, preeclampsia, placental abruption, or small for gestational age (SGA) neonates in a low-risk, prospective cohort., Methods: This was a secondary analysis of the Eunice Kennedy Shriver National Institute of Child Health and Human Development factor V Leiden study, a multicenter, prospective, observational cohort of 5,188 unselected singleton gestations. A total of 4,167 first-trimester samples were available for analysis and were tested for the prothrombin G20210A mutation. Obstetric complications were compared between women with and without the prothrombin G20210A mutation by univariable and multivariable analysis., Results: A total of 157 (3.8%) women had the prothrombin gene mutation (156 heterozygous and one homozygous). Carriers of the prothrombin G20210A mutation had similar rates of pregnancy loss, preeclampsia, SGA neonates, and abruption compared with noncarriers. Results were similar in a multivariable analysis controlling for age, race, prior pregnancy loss, prior SGA neonates, and family history of thromboembolism. Three thromboembolic events occurred in women testing negative for the mutation., Conclusion: There was no association between the prothrombin G20210A mutation and pregnancy loss, preeclampsia, abruption, or SGA neonates in a low-risk, prospective cohort. These data raise questions about the practice of screening women without a history of thrombosis or adverse pregnancy outcomes for this mutation., Level of Evidence: II.

Objective: To estimate the rate of vaginal birth after cesarean delivery (VBAC) success in diabetic women based on White's Classification., Methods: This is a secondary analysis of an observational study conducted at 19 medical centers of women attempting VBAC. Diabetic women with singleton gestations, one prior cesarean delivery, and cephalic presentation who underwent a trial of labor were included. Vaginal birth after cesarean delivery success rates and maternal and neonatal complications were compared based on White's Classification., Results: Of 11,856 women who underwent trial of labor, 624 met all study criteria (class A1, 356; A2, 169; B, 70; C, 21; D/R/F, 8). Vaginal birth after cesarean delivery success in each group was: A1, 68.5% (95% confidence interval [CI] 63.4-73.3%); A2, 55% (95% CI 47.2-62.7%); B, 70% (95% CI 57.9-80.4%); C, 47.6% (95% CI 25.7-70.2%); and D/F/R, 12.5% (95% CI 0.3-52.7%). Maternal and neonatal complications were rare and not found to be different among groups., Conclusion: Our study provides estimates for VBAC success based on White's classification and indicates a relatively low rate of perinatal complications after VBAC attempt for diabetic women., Level of Evidence: III.

Objective: To compare maternal and neonatal outcomes in women undergoing second-stage cesarean delivery after a trial of operative vaginal delivery with those in women undergoing second-stage cesarean delivery without such an attempt., Methods: This study is a secondary analysis of the women who underwent second-stage cesarean delivery. The maternal outcomes examined included blood transfusion, endometritis, wound complication, anesthesia use, and maternal death. Neonatal outcomes examined included umbilical artery pH less than 7.0, Apgar score of 3 or less at 5 minutes, seizures within 24 hours of birth, hypoxic ischemic encephalopathy, stillbirth, skull fracture, and neonatal death., Results: Of 3,189 women who underwent second-stage cesarean delivery, operative vaginal delivery was attempted in 640. Labor characteristics were similar in the two groups, with the exception of the admission-to-delivery time and cesarean indication. Those with an attempted operative vaginal delivery were more likely to undergo cesarean delivery for a nonreassuring fetal heart rate tracing (18.0% compared with 13.9%, P=.01), have a wound complication (2.7% compared with 1.0%, odds ratio [OR] 2.65, 95% confidence interval [CI] 1.43-4.91), and require general anesthesia (8.0% compared with 4.1%, OR 2.05, 95% CI 1.44-2.91). Neonatal outcomes, including umbilical artery pH less than 7.0, Apgar score of 3 or less at 5 minutes, and hypoxic ischemic encephalopathy, were more common for those with an attempted operative vaginal delivery. This was not significant when cases with a nonreassuring fetal heart rate tracing were removed., Conclusion: Cesarean delivery after an attempt at operative vaginal delivery was not associated with adverse neonatal outcomes in the absence of a nonreassuring fetal heart rate tracing., Level of Evidence: II.

Background: Because of increased rates of respiratory complications, elective cesarean delivery is discouraged before 39 weeks of gestation unless there is evidence of fetal lung maturity. We assessed associations between elective cesarean delivery at term (37 weeks of gestation or longer) but before 39 weeks of gestation and neonatal outcomes., Methods: We studied a cohort of consecutive patients undergoing repeat cesarean sections performed at 19 centers of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network from 1999 through 2002. Women with viable singleton pregnancies delivered electively (i.e., before the onset of labor and without any recognized indications for delivery before 39 weeks of gestation) were included. The primary outcome was the composite of neonatal death and any of several adverse events, including respiratory complications, treated hypoglycemia, newborn sepsis, and admission to the neonatal intensive care unit (ICU)., Results: Of 24,077 repeat cesarean deliveries at term, 13,258 were performed electively; of these, 35.8% were performed before 39 completed weeks of gestation (6.3% at 37 weeks and 29.5% at 38 weeks) and 49.1% at 39 weeks of gestation. One neonatal death occurred. As compared with births at 39 weeks, births at 37 weeks and at 38 weeks were associated with an increased risk of the primary outcome (adjusted odds ratio for births at 37 weeks, 2.1; 95% confidence interval [CI], 1.7 to 2.5; adjusted odds ratio for births at 38 weeks, 1.5; 95% CI, 1.3 to 1.7; P for trend <0.001). The rates of adverse respiratory outcomes, mechanical ventilation, newborn sepsis, hypoglycemia, admission to the neonatal ICU, and hospitalization for 5 days or more were increased by a factor of 1.8 to 4.2 for births at 37 weeks and 1.3 to 2.1 for births at 38 weeks., Conclusions: Elective repeat cesarean delivery before 39 weeks of gestation is common and is associated with respiratory and other adverse neonatal outcomes., (2009 Massachusetts Medical Society)

Objective: To examine maternal and infant outcomes after a vaginal delivery of twin A and a cesarean delivery of twin B, and to identify whether the second twin experienced increased short-term morbidity as part of a combined route of delivery., Methods: Between January 1, 1999, and December 31, 2000, a prospective cohort study of all cesarean deliveries was conducted at 13 university centers. This secondary analysis was limited to women with twin gestations who experienced labor and underwent cesarean delivery. We compared outcomes of the second twin in women who had vaginal delivery of the first twin and a cesarean delivery of the second twin to those who had cesarean delivery of both twins., Results: One thousand twenty-eight twin pregnancies experienced labor and underwent cesarean delivery; 179 (17%) had a combined vaginal/cesarean delivery. Gestational age at delivery was 34.6 weeks in both groups (P=.97). The rupture of membranes to delivery interval was longer in the combined group (3.2 compared with 2.3 hours, P<.001). Endometritis and culture-proven sepsis in the second twin were more common in the combined group, respectively (n=24, odds ratio 1.6, 95% confidence interval, 1.0-2.7; n=15, odds ratio 1.8, 95% confidence interval, 1.0-3.4). These differences were not significant after logistic regression analysis. There were no statistically significant differences in an arterial cord pH of less than 7.0, Apgar score less than or equal to 3 at 5 minutes, seizures, grade III or IV intraventricular hemorrhage, hypoxic ischemic encephalopathy, or neonatal death., Conclusion: Combined twin delivery may be associated with endometritis and neonatal sepsis when compared with a twin delivery where both are delivered by cesarean in twin pregnancies experiencing labor. More serious neonatal sequelae, including hypoxic ischemic encephalopathy and death, were not affected by the route of delivery of the second twin.

Objective: To estimate the success rates and risks of an attempted vaginal birth after cesarean delivery (VBAC) according to the number of prior successful VBACs., Methods: From a prospective multicenter registry collected at 19 clinical centers from 1999 to 2002, we selected women with one or more prior low transverse cesarean deliveries who attempted a VBAC in the current pregnancy. Outcomes were compared according to the number of prior VBAC attempts subsequent to the last cesarean delivery., Results: Among 13,532 women meeting eligibility criteria, VBAC success increased with increasing number of prior VBACs: 63.3%, 87.6%, 90.9%, 90.6%, and 91.6% for those with 0, 1, 2, 3, and 4 or more prior VBACs, respectively (P<.001). The rate of uterine rupture decreased after the first successful VBAC and did not increase thereafter: 0.87%, 0.45%, 0.38%, 0.54%, 0.52% (P=.03). The risk of uterine dehiscence and other peripartum complications also declined statistically after the first successful VBAC. No increase in neonatal morbidities was seen with increasing VBAC number thereafter., Conclusion: Women with prior successful VBAC attempts are at low risk for maternal and neonatal complications during subsequent VBAC attempts. An increasing number of prior VBACs is associated with a greater probability of VBAC success, as well as a lower risk of uterine rupture and perinatal complications in the current pregnancy., Level of Evidence: II.

Objective: To estimate the association between the number of prior cesarean deliveries and pregnancy outcomes among women with placenta previa., Methods: Women with a placenta previa and a singleton gestation were identified in a concurrently collected database of cesarean deliveries performed at 19 academic centers during a 4-year period. Maternal and perinatal outcomes were analyzed after stratifying by the number of cesarean deliveries before the index pregnancy., Results: Of the 868 women in the analysis, 488 had no prior cesarean delivery, 252 had one prior cesarean delivery, 76 had two prior cesarean deliveries, and 52 had at least three prior cesarean deliveries. Multiple measures of maternal morbidity (eg, coagulopathy, hysterectomy, pulmonary edema) increased in frequency as the number of prior cesarean deliveries rose. Even one prior cesarean delivery was sufficient to increase the risk of an adverse maternal outcome (a composite of transfusion, hysterectomy, operative injury, coagulopathy, venous thromboembolism, pulmonary edema, or death) from 15% to 23%, which corresponded, in multivariable analysis, to an adjusted odds ratio of 1.9 (95% confidence interval 1.2-2.9). Conversely, gestational age at delivery and adverse perinatal outcome (a composite measure of respiratory distress syndrome, necrotizing enterocolitis, intraventricular hemorrhage grade 3 or 4, seizures, or death) were unrelated to the number of prior cesarean deliveries., Conclusion: Among women with a placenta previa, an increasing number of prior cesarean deliveries is associated with increasing maternal, but not perinatal, morbidity., Level of Evidence: II.

Objective: Current information on the risk of uterine rupture after cesarean delivery has generally compared the risk after trial of labor to that occurring with an elective cesarean delivery without labor. Because antepartum counseling cannot account for whether a woman will develop an indication requiring a repeat cesarean delivery or whether labor will occur before scheduled cesarean delivery, the purpose of this analysis was to provide clinically useful information regarding the risks of uterine rupture and adverse perinatal outcome for women at term with a history of prior cesarean delivery., Methods: Women with a term singleton gestation and prior cesarean delivery were studied over 4 years at 19 centers. For this analysis, outcomes from five groups were studied: trial of labor, elective repeat with no labor, elective repeat with labor (women presenting in early labor who subsequently underwent cesarean delivery), indicated repeat with labor, and indicated repeat without labor. All cases of uterine rupture were reviewed centrally to assure accuracy of diagnosis., Results: A total of 39,117 women were studied. In term pregnant women with a prior cesarean delivery, the overall risk for uterine rupture was 0.32% (125 of 39,117), and the overall risk for serious adverse perinatal outcome (stillbirth, hypoxic ischemic encephalopathy, neonatal death) was 106 of 39,049 (0.27%). The uterine rupture risk for indicated repeat cesarean delivery (labor or without labor) was 7 of 6,080 (0.12%); the risk for elective (no indication) repeat cesarean delivery (labor or without labor) was 4 of 17,714 (0.02%). Indicated repeat cesarean delivery increased the risk of uterine rupture by a factor of 5 (odds ratio 5.1, 95% confidence interval 1.49-17.44). In the absence of an indication, the presence of labor also increased the risk of uterine rupture (4 of 2,721 [0.15%] compared with 0 of 14,993, P<.01). The highest rate of uterine rupture occurred in women undergoing trial of labor (0.74%, 114 of 15,323)., Conclusion: At term, the risk of uterine rupture and adverse perinatal outcome for women with a singleton and prior cesarean delivery is low regardless of mode of delivery, occurring in 3 per 1,000 women. Maternal complications occurred in 3-8% of women within the five delivery groups.

Objective: To compare maternal and neonatal outcomes when primary cesarean delivery is performed in the second stage of labor compared with the first stage., Methods: Between January 1, 1999, and December 31, 2000, a prospective observational study of primary cesarean deliveries was conducted at 13 university centers comprising the National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network. The primary outcomes of interest included a maternal composite (composed of at least one of the following: endometritis, intraoperative surgical complication, blood transfusion, or wound complication) and neonatal composite (which included at least one of the following: Apgar score of 3 or less at 5 minutes, neonatal death, neonatal intensive care unit admission, seizure, delivery room intubation in the absence of meconium, or fetal injury)., Results: A total of 11,981 cesarean deliveries were available for analysis: 9,265 were performed in the first stage and 2,716 in the second stage. Cesarean deliveries performed in the second stage were associated with longer operative times, epidural analgesia, chorioamnionitis, and higher birth weight (all P<.001). The maternal composite index was slightly increased in women undergoing cesarean delivery in the second stage of labor, primarily due to uterine atony, uterine incision extension, and incidental cystotomy. This difference was significant after multivariable analysis (odds ratio 1.21, 95% confidence interval 1.07-1.37). After multivariable analysis, the neonatal composite did not differ significantly between groups (odds ratio 0.96, 95% confidence interval 0.84-1.08)., Conclusion: Cesarean delivery in the second stage of labor is associated with slightly increased maternal but not neonatal composite morbidity., Level of Evidence: II.

Objective: To compare pregnancy outcomes in women with one prior low-transverse cesarean delivery after induction of labor with pregnancy outcomes after spontaneous labor., Methods: This study is an analysis of women with one prior low-transverse cesarean and a singleton gestation who underwent a trial of labor and who were enrolled in a 4-year prospective observational study. Pregnancy outcomes were evaluated according to whether a woman underwent spontaneous labor or labor induction., Results: Among the 11,778 women studied, vaginal delivery was less likely after induction of labor both in women without and with a prior vaginal delivery (51% versus 65%, P<.001; and 83% versus 88%, P<.001). An increased risk of uterine rupture after labor induction was found only in women with no prior vaginal delivery (1.5% versus 0.8%, P=.02; and 0.6% versus 0.4%, P=.42). Blood transfusion, venous thromboembolism, and hysterectomy were also more common with induction among women without a prior vaginal delivery. No measure of perinatal morbidity was associated with labor induction. An unfavorable cervix at labor induction was not associated with any adverse outcomes except an increased risk of cesarean delivery., Conclusion: Induction of labor in the study population is associated with an increased risk of cesarean delivery in all women with an unfavorable cervix, a statistically significant, albeit clinically small, increase in maternal morbidity in women with no prior vaginal delivery, and no appreciable increase in perinatal morbidity., Level of Evidence: II.

Objective: The purpose of this study was to determine if weekly corticosteroids improve neonatal outcome without undue harm., Study Design: Women 23 to 32 weeks receiving 1 course of corticosteroids 7 to 10 days prior were randomized to weekly betamethasone or placebo., Results: The study was terminated by the independent data and safety monitoring committee with 495 of the anticipated 2400 patients enrolled. There was no significant reduction in the composite primary morbidity outcome (8.0% vs 9.1%, P = .67). Repeated courses significantly reduced neonatal surfactant administration (P = .02), mechanical ventilation (P = .004), CPAP (P = .05), pneumothoraces (P = .03). There was no significant difference in mean birth weight or head circumference. The repeat group had a reduction in multiples of the birth weight median by gestational age (0.88 vs 0.91) (P = .01) and more neonates weighing less than the 10th percentile (23.7 vs 15.3%, P = .02). Significant weight reductions occurred for the group receiving > or = 4 courses., Conclusion: Repeat antenatal corticosteroids significantly reduce specific neonatal morbidities but do not improve composite neonatal outcome. This is accompanied by reduction in birth weight and increase in small for gestational age infants.

Objective: Assess effects of body mass index (BMI) on trial of labor after previous cesarean delivery and determine whether morbidly obese women have greater maternal and perinatal morbidity with trial of labor compared with elective repeat cesarean delivery., Methods: Secondary analysis from a prospective observational study included all term singletons undergoing trial of labor after previous cesarean delivery. Body mass index groups were as follows: normal 18.5-24.9, overweight 25.0-29.9, obese 30.0-39.9, morbidly obese 40.0 kg/m2 or greater, and were compared for failure and maternal and neonatal morbidities. The morbidly obese trial of labor and elective repeat cesarean delivery were compared for maternal and neonatal morbidities. Multivariable logistic regression analysis controlled for confounding variables., Results: There were 14,142 trial of labor participants and 14,304 elective repeat cesarean delivery participants. Increasing BMI was directly associated with failed trial of labor after previous cesarean delivery: from 15.2% in normal weight (1,344) to 39.3% in morbidly obese (1,638), with combined risk of rupture/dehiscence increasing from 0.9% to 2.1% in morbidly obese women. Among morbidly obese women, trial of labor carried greater than five-fold risk of uterine rupture/dehiscence (2.1% versus 0.4%), almost a two-fold increase in composite maternal morbidity (7.2% versus 3.8%) and five-fold risk of neonatal injury (1.1% versus 0.2%) (fractures, brachial plexus injuries, and lacerations), but no neonatal encephalopathy. Morbidly obese women failing a trial of labor had six-fold greater composite maternal morbidity than those undergoing a successful trial of labor (14.2% versus 2.6%)., Conclusion: Body mass index correlates with outcomes in trial of labor after previous cesarean delivery. Morbidly obese women undergoing a trial of labor were at increased risk for failure. Increased BMI was associated with greater composite morbidity and neonatal injury compared with elective repeat cesarean delivery, but absolute morbidities were small. Increased risks should be considered before trial of labor after previous cesarean delivery., Level of Evidence: II-2.

Background: Data on complications of pregnancy associated with antiretroviral therapy are limited. Some small studies have demonstrated an increased preterm delivery rate, but a recent retrospective United States multisite study did not concur with these findings. Our objective was to investigate whether antiretroviral therapy was associated with adverse pregnancy outcome at a single site., Methods: Using prospectively gathered data, women were identified who were determined to be human immunodeficiency virus positive before or during pregnancy who sought care at our prenatal clinic and who gave birth at the University of Miami/Jackson Memorial Medical Center from 1990 through 2002. The outcome measures were preterm delivery, low birth weight, and stillbirth., Results: The cohort included 999 women who received antiretroviral therapy during pregnancy (monotherapy in 492, combination therapy without a protease inhibitor [PI] in 373, and combination therapy with a PI in 134) and 338 women who did not receive therapy. After adjustment for possible confounders, only combination therapy with a PI was associated with an increased risk of preterm delivery, compared with any other combination (odds ratio, 1.8 [95% confidence interval, 1.1-3.0]). There were no differences in rates of low birth weight and stillbirth, regardless of therapy., Conclusion: Compared with monotherapy and combination therapy without a PI, only combination therapy with a PI was associated with an increased risk of preterm delivery.

Objective: The purpose of this study was to test the hypothesis that maternal asthma symptoms and pulmonary function are related to adverse perinatal outcomes., Study Design: Asthmatic patients were recruited from the 16 centers of the Maternal Fetal Medicine Units. Forced expiratory volume in 1 second was obtained at enrollment and at monthly study visits, and the frequency of asthma symptoms was assessed from enrollment to delivery. Perinatal data were obtained at postpartum chart reviews., Results: The final cohort included 2123 participants with asthma. After adjustment for demographic characteristics, smoking, acute asthmatic episodes, and oral corticosteroid use, significant relationships were demonstrated between gestational hypertension and preterm birth and lower maternal gestational forced expiratory volume in 1 second. The data did not show any significant independent relationship between asthma symptom frequency and perinatal outcomes., Conclusion: Lower pulmonary function during pregnancy is associated with increased gestational hypertension and prematurity in the pregnancies of women with asthma, which may be due to inadequate asthma control or factors that are associated with increased asthma severity.

We report a 26-year-old woman with congenital hepatic fibrosis (CHFib), adult polycystic kidney disease, type II diabetes mellitus, and von Willebrand disease, who despite persistent advice to the contrary because of severe portal hypertension, had 5 pregnancies delivering 6 healthy infants over 8 yr. During this time, she experienced several episodes of esophageal variceal bleeding and severe ascites with persistently normal liver and renal function. CHFib is one of the prototypes of portal hypertension with preserved hepatocellular function. Although pregnancy is ill-advised in most women with portal hypertension and particularly with severe manifestations, this report illustrates the importance of preserved hepatocellular function for the outcome of pregnancy in these patients.

Objective: We sought to estimate the frequency of pregnancy-related thromboembolic events among carriers of the factor V Leiden (FVL) mutation without a personal history of thromboembolism, and to evaluate the impact of maternal and fetal FVL mutation carriage or other thrombophilias on the risk of adverse outcomes., Methods: Women with a singleton pregnancy and no history of thromboembolism were recruited at 13 clinical centers before 14 weeks of gestation from April 2000 to August 2001. Each was tested for the FVL mutation, as was the resultant conceptus after delivery or after miscarriage, when available. The incidence of thromboembolism (primary outcome), and of other adverse outcomes, was compared between FVL mutation carriers and noncarriers. We also compared adverse outcomes in a secondary nested carrier-control analysis of FVL mutation and other coagulation abnormalities. In this secondary analysis, we defined carriers as women having one or more of the following traits: carrier for FVL mutation, protein C deficiency, protein S deficiency, antithrombin III deficiency, activated protein C resistance, or lupus anticoagulant-positive, heterozygous for prothrombin G20210A or homozygous for the 5,10 methylenetetrahydrofolate reductase mutations. Carriers of the FVL mutation alone (with or without activated protein C resistance) were compared with those having one or more other coagulation abnormalities and with controls with no coagulation abnormality., Results: One hundred thirty-four FVL mutation carriers were identified among 4,885 gravidas (2.7%), with both FVL mutation status and pregnancy outcomes available. No thromboembolic events occurred among the FVL mutation carriers (0%, 95% confidence interval 0-2.7%). Three pulmonary emboli and one deep venous thrombosis occurred (0.08%, 95% confidence interval 0.02-0.21%), all occurring in FVL mutation noncarriers. In the nested carrier-control analysis (n = 339), no differences in adverse pregnancy outcomes were observed between FVL mutation carriers, carriers of other coagulation disorders, and controls. Maternal FVL mutation carriage was not associated with increased pregnancy loss, preeclampsia, placental abruption, or small for gestational age births. However, fetal FVL mutation carriage was associated with more frequent preeclampsia among African-American (15.0%) and Hispanic (12.5%) women than white women (2.6%, P = .04), adjusted odds ratio 2.4 (95% confidence interval 1.0-5.2, P = .05)., Conclusion: Among women with no history of thromboembolism, maternal heterozygous carriage of the FVL mutation is associated with a low risk of venous thromboembolism in pregnancy. Neither universal screening for the FVL mutation, nor treatment of low-risk carriers during pregnancy is indicated., Level of Evidence: II-2.

Background: The proportion of women who attempt vaginal delivery after prior cesarean delivery has decreased largely because of concern about safety. The absolute and relative risks associated with a trial of labor in women with a history of cesarean delivery, as compared with elective repeated cesarean delivery without labor, are uncertain., Methods: We conducted a prospective four-year observational study of all women with a singleton gestation and a prior cesarean delivery at 19 academic medical centers. Maternal and perinatal outcomes were compared between women who underwent a trial of labor and women who had an elective repeated cesarean delivery without labor., Results: Vaginal delivery was attempted by 17,898 women, and 15,801 women underwent elective repeated cesarean delivery without labor. Symptomatic uterine rupture occurred in 124 women who underwent a trial of labor (0.7 percent). Hypoxic-ischemic encephalopathy occurred in no infants whose mothers underwent elective repeated cesarean delivery and in 12 infants born at term whose mothers underwent a trial of labor (P<0.001). Seven of these cases of hypoxic-ischemic encephalopathy followed uterine rupture (absolute risk, 0.46 per 1000 women at term undergoing a trial of labor), including two neonatal deaths. The rate of endometritis was higher in women undergoing a trial of labor than in women undergoing repeated elective cesarean delivery (2.9 percent vs. 1.8 percent), as was the rate of blood transfusion (1.7 percent vs. 1.0 percent). The frequency of hysterectomy and of maternal death did not differ significantly between groups (0.2 percent vs. 0.3 percent, and 0.02 percent vs. 0.04 percent, respectively)., Conclusions: A trial of labor after prior cesarean delivery is associated with a greater perinatal risk than is elective repeated cesarean delivery without labor, although absolute risks are low. This information is relevant for counseling women about their choices after a cesarean section., (Copyright 2004 Massachusetts Medical Society.)

Objective: To evaluate the outcomes of pregnancies with sonographically detected nuchal cords remote from delivery during the second and third trimesters of gestation., Methods: A retrospective study of patients with and without nuchal cords detected by sonography during the second and third trimesters of gestation (17-36 weeks) was conducted. Variables included maternal age, parity, gestational age at sonography and at delivery, method of delivery, intrapartum fetal heart abnormalities, meconium-stained amniotic fluid, birth weight, 5-minute Apgar score, and neonatal intensive care unit admissions., Results: A total of 233 patients were included in this study, of which 118 had sonographically detected nuchal cords identified in our department during the study period. There were no statistically significant differences between patients with sonographically detected nuchal cords and control patients with respect to maternal age, estimated gestational age at sonography, method of delivery, meconium-stained fluid, birth weight, intrapartum fetal heart abnormalities, 5-minute Apgar scores of less than 7, and neonatal intensive care unit admissions. Patients with nuchal cords detected by sonography were more likely to give birth before 37 weeks' gestation than control patients (21% versus 11%; P = .040)., Conclusions: A sonographically detected nuchal cord is not associated with important perinatal complications.

Background: Women who have had a spontaneous preterm delivery are at greatly increased risk for preterm delivery in subsequent pregnancies. The results of several small trials have suggested that 17 alpha-hydroxyprogesterone caproate (17P) may reduce the risk of preterm delivery., Methods: We conducted a double-blind, placebo-controlled trial involving pregnant women with a documented history of spontaneous preterm delivery. Women were enrolled at 19 clinical centers at 16 to 20 weeks of gestation and randomly assigned by a central data center, in a 2:1 ratio, to receive either weekly injections of 250 mg of 17P or weekly injections of an inert oil placebo; injections were continued until delivery or to 36 weeks of gestation. The primary outcome was preterm delivery before 37 weeks of gestation. Analysis was performed according to the intention-to-treat principle., Results: Base-line characteristics of the 310 women in the progesterone group and the 153 women in the placebo group were similar. Treatment with 17P significantly reduced the risk of delivery at less than 37 weeks of gestation (incidence, 36.3 percent in the progesterone group vs. 54.9 percent in the placebo group; relative risk, 0.66 [95 percent confidence interval, 0.54 to 0.81]), delivery at less than 35 weeks of gestation (incidence, 20.6 percent vs. 30.7 percent; relative risk, 0.67 [95 percent confidence interval, 0.48 to 0.93]), and delivery at less than 32 weeks of gestation (11.4 percent vs. 19.6 percent; relative risk, 0.58 [95 percent confidence interval, 0.37 to 0.91]). Infants of women treated with 17P had significantly lower rates of necrotizing enterocolitis, intraventricular hemorrhage, and need for supplemental oxygen., Conclusions: Weekly injections of 17P resulted in a substantial reduction in the rate of recurrent preterm delivery among women who were at particularly high risk for preterm delivery and reduced the likelihood of several complications in their infants., (Copyright 2003 Massachusetts Medical Society)

Background: Some studies suggest that combination antiretroviral therapy in pregnant women with human immunodeficiency virus type 1 (HIV-1) infection increases the risk of premature birth and other adverse outcomes of pregnancy., Methods: We studied pregnant women with HIV-1 infection who were enrolled in seven clinical studies and delivered their infants from 1990 through 1998. The cohort comprised 2123 women who received antiretroviral therapy during pregnancy (monotherapy in 1590, combination therapy without protease inhibitors in 396, and combination therapy with protease inhibitors in 137) and 1143 women who did not receive antiretroviral therapy., Results: After standardization for the CD4+ cell count and use or nonuse of tobacco, alcohol, and illicit drugs, the rate of premature delivery (<37 weeks of gestation) was similar among the women who received antiretroviral therapy and those who did not (16 percent and 17 percent, respectively); the rate of low birth weight (<2500 g) was 16 percent among the infants born to both groups; and the rate of very low birth weight (<1500 g) was 2 percent for the group that received antiretroviral therapy and 1 percent for the group that did not. The rates of low Apgar scores (<7) and stillbirth were also similar or the same in the two groups. After adjustment for multiple risk factors, combination antiretroviral therapy was not associated with an increased risk of premature delivery as compared with monotherapy (odds ratio, 1.08; 95 percent confidence interval, 0.71 to 1.62) or delivery of an infant with low birth weight (odds ratio, 1.03; 95 percent confidence interval, 0.64 to 1.63). Seven of the women who received combination therapy with protease inhibitors (5 percent) had infants with very low birth weight, as compared with nine women who received combination therapy without protease inhibitors (2 percent) (adjusted odds ratio, 3.56; 95 percent confidence interval, 1.04 to 12.19)., Conclusions: As compared with no antiretroviral therapy or monotherapy, combination therapy for HIV-1 infection in pregnant women is not associated with increased rates of premature delivery or with low birth weight, low Apgar scores, or stillbirth in their infants. The association between combination therapy with protease inhibitors and an increased risk of very low birth weight requires confirmation.

Objective: To determine whether one structurally affected fetus of a twin pregnancy further increases the risk of preterm delivery and to compare perinatal morbidity and mortality in these pregnancies with twin gestations with structurally normal fetuses., Study Design: The cases (n = 25) included all twin gestations diagnosed from 1991 to 1994 with a sonographically detected fetal anomaly and a structurally normal co-twin delivered after 24 completed weeks' gestation. The control group consisted of 547 twin gestations delivered during the study period with no sonographically detected structural anomalies in either twin., Results: Compared with controls, pregnancies with a single anomalous fetus (cases) delivered at a significantly lower gestational age (mean +/- SD: 34.0 +/- 3.2 weeks versus 35.6 +/- 3.2 weeks; p = 0.019) and had a significantly increased preterm delivery rate (76.0% vs 55.4%; p = 0.042). There was no significant difference in the incidence of intraventricular hemorrhage or respiratory distress syndrome, yet the perinatal mortality (80.0/1000 vs 6.4/1000; p = 0.000) and the average nursery stay (45.5 +/- 43.3 days versus 17.0 +/- 24.0 days; p = 0.003) were significantly increased for cases compared with controls. In addition, a significantly greater birth weight discordancy (> or = 30%) was seen in cases compared with controls (32.0% versus 9.1%; p = 0.002). The normal co-twin did not show any significant difference in the perinatal outcome variables studied when compared with controls., Conclusion: Compared with structurally normal twin pairs, twin gestations with a single anomalous fetus are at a significantly increased risk for preterm delivery. In addition, the anomalous fetus, but not the structurally normal co-twin, has a significantly increased mortality rate and a longer nursery stay. Finally, despite the increased risk for preterm delivery in twin pregnancies with one anomalous fetus, it is the nature of the anomaly itself that dictates the perinatal outcome.