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Objective: The purpose of this study was to identify the success rates and risks in women with a twin pregnancy who attempt a trial of labor after cesarean delivery., Study Design: Cases were identified in the National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network's Cesarean Registry with a woman with a twin pregnancy who had had at least 1 previous cesarean delivery., Results: During the study period (1999-2002), 412 women fulfilled the study criteria, and 226 women had elective repeat cesarean delivery. Of the 186 women (45.1% of total) who attempted a trial of labor, 120 women were delivered successfully (success rate, 64.5%), and 66 women (35.5%) had a failed trial of labor. Thirty of the failed trials of labor involved a vaginal delivery for twin A and cesarean delivery for twin B. Women who attempted a trial of labor with twins had no increased risk of transfusion, endometritis, intensive care unit admissions, or uterine rupture when compared with elective repeat cesarean delivery. Fetal and neonatal complications were uncommon in either group at>or=34 weeks of gestation., Conclusion: A trial of labor with twins after previous cesarean delivery does not appear to increase maternal morbidity. Perinatal morbidity is uncommon at>or=34 weeks of gestation.

Objective: Studies suggest that sleep deprivation adversely affects performance. We hypothesized that cesarean delivery complications would be more frequent during the night shift (11 PM–7 AM), and evaluated morbidities by delivery shift. Study design: Eighteen thousand nine hundred and thirty-nine term women undergoing an unscheduled cesarean delivery in 13 centers from 1999 to 2000 within a prospective observational study were included. Maternal/neonatal morbidities and time from decision to cesarean delivery were evaluated by time of delivery (7 AM–3 PM, 3 PM–11 PM, 11 PM–7 AM). A composite of maternal morbidities was evaluated by logistic regression controlling for potentially confounding factors. Results: Controlling for age, race, insurance, cardiac disease, preeclampsia, diabetes, previous incision type, and prenatal care, shift of delivery had no impact on maternal morbidity (11 PM–7 AM OR 0.9 [95% CI 0.81–1.0]). NICU admissions were slightly increased at night but neonatal complications were not. Conclusion: Maternal and neonatal complications of cesarean delivery do not increase with delivery during the night shift. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study was to determine the influence of change in infant birth weight between pregnancies on the outcome of a trial of labor for women whose first cesarean delivery was performed for dystocia. Study design: Secondary analysis of 7081 patients with 1 previous cesarean delivery and no other deliveries after 20 weeks' gestation, undergoing a trial of labor with a singleton gestation. Cases were classified as dystocia if the listed indication for the cesarean delivery in the first pregnancy was failed induction, cephalo-pelvic disproportion, failure to progress, or failed forceps or vacuum. Outcomes of the trial of labor were correlated with fetal size relative to birth weight in the initial pregnancy for those women whose initial cesarean delivery was for dystocia and those with other indications. Results: For the cohort being studied (n = 7081), dystocia was the indication for the first cesarean delivery for 3182 (44.9%). Trial of labor resulted in vaginal delivery for 54% of patients whose first cesarean delivery was performed for dystocia, compared with 67% for those with other indications (P < .01). For those whose first cesarean delivery was for dystocia, trial of labor success was correlated with birth weight differences between the pregnancies, with only 38% delivering vaginally if the trial of labor birth weight exceeded the initial pregnancy birth weight by more than 500 g. Using logistic regression and adjusting for other potential confounding factors, the odds of success decreased by 3.8% for each increase of 100 g in birth weight in the trial of labor relative to the first birth weight. Conclusion: For women with previous cesarean delivery for dystocia, increasing birth weight in the subsequent trial of labor relative to the first birth weight diminishes the chances of successful vaginal delivery. [ABSTRACT FROM AUTHOR]

Objective: This study was undertaken to compare success rates of vaginal birth after cesarean (VBAC) delivery, and uterine rupture as well as maternal/perinatal outcomes between women with preterm and term pregnancies undergoing trial of labor (TOL), and to compare maternal and neonatal morbidities in those women with preterm pregnancies undergoing a TOL versus repeat cesarean delivery without labor (RCD). Study design: Prospective 4-year observational study of women with a singleton gestation and a prior cesarean delivery at 19 academic centers. Clinical characteristics, maternal complications and VBAC delivery success for those with a preterm (240–366 weeks) TOL, preterm RCD and term TOL (≥37 weeks) were analyzed. Results: Among 3119 preterm pregnancies with prior cesarean delivery, 2338 (75%) underwent a TOL. 15,331 women undergoing TOL at term were also analyzed as a control group. TOL success rates for preterm and term pregnancies were similar (72.8% vs 73.3%, P = .64). Rates of uterine rupture (0.34% vs 0.74%, P = .03) and dehiscence (0.26% vs 0.67%, P = .02) were lower in preterm compared with term TOL. Thromboembolic disease, coagulopathy and transfusion were more common in women undergoing a preterm TOL than those at term. Among women undergoing a preterm TOL, rates of uterine dehiscence, coagulopathy, transfusion, and endometritis were similar to those having a preterm RCD. After controlling for gestational age at delivery and race, neonatal outcomes such as Neonatal Intensive Care Unit (N1CU) admission, intraventricular hemorrhage, sepsis, and ventilatory support were similar in both groups except for a higher rate of respiratory distress syndrome in those delivered after a TOL. Conclusion: The likelihood of VBAC success after TOL in preterm pregnancies is comparable to term gestations, with a lower risk of uterine rupture. Perinatal outcomes are similar with preterm TOL and RCD. TOL should be considered as an option for women undergoing preterm delivery with a history of prior cesarean delivery. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study was to define independent risk factors for uterine atony after primary cesarean delivery, and to assess their overall association with atony in the study cohort. Study design: This was a 13-university center prospective observational study. All women who underwent primary cesarean from January 1, 1999 to December 31, 2000 were eligible. Trained and certified research nurses performed systematic data abstraction. The definition of atony required both the clinical diagnosis and the use of methergine or a prostaglandin preparation. Risk factors for uterine atony were assessed in univariable and multivariable logistic regression analyses, and these analyses then used to inform an assessment of the association of the various risk factors with the occurrence of uterine atony in the overall cohort. Results: Twenty-three thousand, three hundred and ninety pregnancies were analyzed. Uterine atony occurred in 1416 women (6%). Several variables were independently associated with atony in a multivariable model, including multiple gestation (odds ratio [OR] 2.40, 95% CI 1.95-2.93), maternal Hispanic race (2.21, 1.90-2.57), induced or augmented labor for >18 hours (2.23, 1.922.60), infant birth weight >4500 g (2.05, 1.53-2.69), and clinically diagnosed chorioamnionitis (1.80, 1.55-2.09). However, because the various risk factors were not very powerful, approximately half of the cases of atony were associated with the 2/3 of women lacking a given risk factor or combination of risk factors. Conclusion: Although certain risk factors and uterine atony were clearly associated, the associations are of limited practical clinical use. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study was to determine which factors influence the likelihood of successful trial of labor (TOL) after 1 previous cesarean delivery (CD). Study design: We performed a multicenter 4-year prospective observational study (1999-2002) of all women with previous CD undergoing TOL. Women with term singleton pregnancies with 1 previous low transverse CD or unknown incision were included for analysis. Results: Fourteen thousand five hundred twenty-nine women underwent TOL, with 10,690 (73.6%) achieving successful VBAC. Women with previous vaginal birth had an 86.6% success rate compared with 60.9% in women without such a history (odds ratio [OR] 4.2; 95% CI 3.8-4.5; P < .001). TOL success rates were affected by previous indication for CD, need for induction or augmentation, cervical dilation on admission, birth weight, race, and maternal body mass index. Multivariate logistic regression analysis identified as predictive of TOL success: previous vaginal delivery (OR 3.9; 95% CI 3.6-4.3), previous indication not being dystocia (CPD/FTP) (OR 1.7; 95% CI 1.5-1.8), spontaneous labor (OR 1.6; 95% CI 1.5-1.8), birth weight <4000 g (OR 2.0; 95% CI 1.8-2.3), and Caucasian race (OR 1.8, 95% CI 1.6-1.9) (all P < .001). The overall TOL success rate in obese women (BMI ⩾30) was lower (68.4%) than in nonobese women (79.6%) (P < .001), and when combined with induction and lack of previous vaginal delivery, successful VBAC occurred in only 44.2% of cases. Conclusion: Previous vaginal delivery including previous VBAC is the greatest predictor for successful TOL. Previous indication as dystocia, need for labor induction, or a maternal BMI ⩾30 significantly lowers success rates. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the relationship between prepregnancy maternal body mass index and spontaneous preterm birth and indicated preterm birth. Study design: This was a secondary analysis of the Maternal-Fetal Medicine Units Network, Preterm Prediction study. Patients were classified into categories that were based on their body mass index. Rates of indicated and spontaneous preterm birth were compared. Results: Five hundred ninety-seven (20.5%) of 2910 women were obese. Obese women had fewer spontaneous preterm births at <37 weeks of gestation (6.2% vs 11.2%; P < .001) and at < 34 weeks of gestation (1.5% vs 3.5%; P = .012). Women with a body mass index of <19 kg/m² had 16.6% spontaneous preterm birth, with a body mass index of 19 to 24.9 kg/m² had 11.3% spontaneous preterm birth, with a body mass index of 25 to 29.9 kg/m² had 8.1% spontaneous preterm birth, with a body mass index of 30 to 34.9 kg/m² had 7.1% spontaneous preterm birth, and with a body mass index of ≥35 kg/m² had 5.2% spontaneous preterm birth (P < .0001). Indicated delivery was responsible for an increasing proportion of preterm births with increasing body mass index (P = .001). Obese women had lower rates of cervical length <25 mm (5% vs 8%; P = .012). Multivariable regression analysis confirmed a lower rate of spontaneous preterm birth in obese gravid women (odds ratio, 0.57; 95% CI, 0.39-0.83; P = .003). Conclusion: Obesity before pregnancy is associated with a lower rate of spontaneous preterm birth. [ABSTRACT FROM AUTHOR]

Objective: Preterm premature rupture of the membranes (PPROM) is believed to be caused, in part, by abnormalities of collagen and increased levels of oxidative stress. Elevated homocysteine levels have been shown to induce these same pathophysiologic changes. We tested the hypothesis that serum homocysteine levels would be higher in women with PPROM when compared with matched control women. Study design: A secondary analysis derived from 2 previously completed studies performed in the National Institutes of Child Health and Human Development Maternal-Fetal Medicine Units (MFMU) Network. We identified 99 study cases with PPROM (24 to 32 weeks' gestation) and matched them with 99 asymptomatic control women from an observational study of preterm birth prediction. Cases and control women were matched for race, gestational age at sampling, and MFMU Network center. Serum homocysteine levels were determined by immunoassay in batch fashion by personnel masked to study arm and clinical outcomes. Serum homocysteine levels were compared between groups, as were the baseline characteristics of maternal age, cigarette smoking, nulliparity, infections during pregnancy, and body mass index (BMI) < 19.8 kg/m2. Serum homocysteine levels were dichotomized as > 75th, 90th, and 95th %ile of control women, and the likelihood of elevated homocysteine levels was determined in women who smoked, had a BMI <19.8 kg/m2, or who had PPROM. Statistical analyses included the Wilcoxon rank sum, chi-square, and Pearson correlation coefficient, where appropriate. Baseline characteristics were controlled with a logistic regression model. Results: Serum homocysteine levels measured in patients with PPROM were not significantly different from matched control women: median and (25th to 75th %ile): 4.9 (3.5–6.2) vs 4.8 (3.9–6.2 μmol/L), P = .73. In our population, neither the number of cigarettes smoked (r = -0.08, P = .57), nor BMI (r = -0.08, P = .24) correlated with serum homocysteine levels. The strongest association was seen in women with PPROM having serum homocysteine levels >95th %ile of control women (odds ratio [OR] 2.7, P = .10). After adjusting for baseline characteristics, no correlation between serum homocysteine level and the presence of PPROM was seen, OR 1.0 (.9–1.1); P = .99. Conclusion: Women presenting with PPROM did not have significantly increased serum homocysteine levels when compared with control women. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study was to evaluate the relationship between chorioamnionitis and its duration to adverse maternal, fetal, and neonatal outcomes. Study design: This was a 13-university center, prospective observational study. All women at term carrying a singleton gestation who underwent primary cesarean from January 1, 1999 to December 31, 2000 were eligible. Data abstraction was systematic and performed by trained research nurses. Selected adverse outcomes were compared between pregnancies with, and without, clinically diagnosed chorioamnionitis using relative risks (RRs) and 95% CIs. The duration of chorioamnionitis was stratified into 5 intervals (≤3 h,>3–6 h,>6–9 h,>9–12 h, and > 12 h), and respective outcomes compared by Mantel-Haenszel test for trend. Additionally, regression analysis was used to compute odds ratios (ORs) and 95% CIs for chorioamnionitis duration length as a continuous explanatory variable. Results: 16,650 pregnancies were analyzed, 1965 (12%) with chorioamnionitis, which was associated with significantly increased risks of maternal blood transfusion, uterine atony, septic pelvic thrombophlebitis, and pelvic abscess (RR 2.3–3.7), as well as 5-minute Apgar ≤3, neonatal sepsis, and seizures (RR 2.1–2.8). By test of trend, only uterine atony (P < .01), maternal blood transfusion (P = .03), maternal admission to intensive care unit (P = .02), and 5-minute Apgar ≤3 (P < .01) were associated with duration of chorioamnionitis. By logistic analysis, only uterine atony (OR for each hour of chorioamnionitis 1.03, 95% CI 1.00–1.06), 5-minute Apgar ≤3 (OR 1.09, 95% CI 1.00–1.16), and neonatal mechanical ventilation within 24 hours of birth (OR 1.07, 95% CI 1.01–1.12) were significantly associated with chorioamnionitis duration. Conclusion: Chorioamnionitis was associated with increased rates of morbidity after cesarean at term. The duration of chorioamnionitis, however, was not related to most measures of adverse maternal or fetal-neonatal outcome. [ABSTRACT FROM AUTHOR]

Objective: This study was undertaken to evaluate the effect of change of shift for physicians and nurses on complications associated with cesarean delivery. Study Design: 17,996 term women undergoing an unscheduled cesarean delivery in 13 centers from 1999-2000 were included. Maternal and neonatal morbidities were evaluated by time of infant delivery vis-à-vis nursing change of shift (6 am-8 am, 2 pm-4 pm, 10 pm-12 am vs all other hours). The sample was then limited to weekdays only and physician shift changes were evaluated (physician shift change 6 am-8 am, 5 pm-7 pm vs all others). A composite of 30 maternal morbidities was also evaluated by logistic regression, controlling for potentially confounding factors. Results: Physician change of shift had no measurable effect on maternal and neonatal outcomes. Neonatal facial nerve palsies were increased at nursing change of shift (5 vs 0) as were hysterectomies (33 [0.24%] vs 23 [0.53%]; P < .007). Nursing change of shift had no impact on composite maternal morbidity after controlling for age, race, insurance, medical problems, prior incision type, weekend day, and prenatal care (odds ratio = 0.98; 95% confidence interval = 0.89-1.08). Conclusion: Physician change of shift does not appear to be associated with an increase in morbidities. However, cesarean delivery during nursing change of shift is associated with increased risk of neonatal facial nerve palsy and hysterectomy. Further investigation is needed to understand the cause of this association. [Copyright &y& Elsevier]

The article presents a comparison of increased risk of subsequent uterine rupture in women with a history of previous preterm and nonclassic term cesarean delivery. Women who had a previous preterm cesarean delivery are at a minimal increased risk of uterine rupture in comparison to women who had previous term cesarean deliveries.

The article presents a study which estimates the success rates and risks of an attempted vaginal birth after cesarean (VBAC) delivery. In this paper, the authors had selected women with one or more prior low transverse cesarean deliveries who attempted a VBAC in the current pregnancy. With this, it has been found that women with prior successful VBAC attempts are at low risk for maternal and neonatal complications during subsequent VBAC attempts.

The article reports on a study which developed a graphic nomogram model based on factors available at the first prenatal visit predicting chance of successful vaginal birth after cesarean delivery for individual patients who undergo a trial of labor. Factors identifiable at the first prenatal visit were used.

The article measures decision-to-incision time intervals and maternal and infant outcomes at multiple university-based hospitals comprising the National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network in the United States. Approximately one-third of primary cesarean deliveries performed for emergency indications are commenced more than 30 minutes after the decision to operate.

Objective: To examine how demographic and pregnancy characteristics can affect the risk of recurrent preterm delivery and the how the effectiveness of progesterone treatment for prevention alters these relationships. Methods: This was a secondary analysis of a randomized trial of 17α-hydroxyprogesterone caproate to prevent recurrent preterm delivery in women at risk. Associations of risk factors for preterm delivery (less than 37 completed weeks of gestation) were examined separately for the women in the 17α-hydroxyprogesterone caproate (n = 310) and placebo (n = 153) groups. Results: Univariate analysis found that the number of previous preterm deliveries and whether the penultimate delivery was preterm were significant risk factors for preterm delivery in both the placebo and progesterone groups. High body mass index was protective of preterm birth in the placebo group. Multivariate analysis found progesterone treatment to cancel the risk of more than 1 previous preterm delivery, but not the risk associated with the penultimate pregnancy delivered preterm. Obesity was associated with lower risk for preterm delivery in the placebo group but not in the women treated with progesterone. Conclusion: The use of 17α-hydroxyprogesterone caproate in women with a previous preterm delivery reduces the overall risk of preterm delivery and changes the epidemiology of risk factors for recurrent preterm delivery. In particular, these data suggest that 17α-hydroxyprogesterone caproate reduces the risk of a history of more than 1 preterm delivery. [ABSTRACT FROM AUTHOR]