Repeated courses of antenatal corticosteroids: are there effects on the infant's auditory brainstem responses?

Our objective was to assess the effects of repeated antenatal corticosteroid treatments on the neonatal auditory brainstem response (ABR), a sensitive measure of neonatal brain maturity and auditory function. To achieve this, we performed and blindly evaluated neonatal ABRs on a subset of infants delivering within a multicenter randomized placebo-controlled clinical trial comparing single versus repeated courses of antenatal corticosteroid treatments for women at 23-31 weeks gestation who remained at increased risk for preterm birth. The women were randomly assigned to either the single or the repeated antenatal corticosteroid treatment group. Women in the repeated antenatal corticosteroid group received weekly antenatal corticosteroid treatments until 34 weeks gestation or until they reached a study-determined limited number of courses, whereas women in the single antenatal corticosteroid group received an initial course of corticosteroid followed by weekly placebo injections. We performed ABR testing on their infants prior to discharge. The latencies of waves I, III and V and the peak-to-trough amplitudes of waves I and V were compared between those in the single (n=27) and repeated antenatal corticosteroid treatment (n=24) groups. The majority of repeated antenatal corticosteroid infants (20 of 24) were exposed to ≥ 4 antenatal corticosteroid treatments. Even though gestational age was similar between our subset of single and repeated antenatal corticosteroid treatment groups, infant birth weight and length and head circumference were significantly smaller in the repeated antenatal corticosteroid group (p <0.05). Despite these differences in birth sizes, there were no significant group differences in the ABR wave latencies or amplitudes. We concluded that our repeated antenatal corticosteroid treatments, in comparison to a single treatment, did not significantly benefit or harm the neonatal ABR despite significant effects on birth size.

Does information available at admission for delivery improve prediction of vaginal birth after cesarean?

We sought to construct a predictive model for vaginal birth after cesarean (VBAC) that combines factors that can be ascertained only as the pregnancy progresses with those known at initiation of prenatal care. Using multivariable modeling, we constructed a predictive model for VBAC that included patient factors known at the initial prenatal visit as well as those that only become evident as the pregnancy progresses to the admission for delivery. We analyzed 9616 women. The regression equation for VBAC success included multiple factors that could not be known at the first prenatal visit. The area under the curve for this model was significantly greater ( P < 0.001) than that of a model that included only factors available at the first prenatal visit. A prediction model for VBAC success, which incorporates factors that can be ascertained only as the pregnancy progresses, adds to the predictive accuracy of a model that uses only factors available at a first prenatal visit.

Timing of elective repeat cesarean delivery at term and neonatal outcomes.

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.

Can a prediction model for vaginal birth after cesarean also predict the probability of morbidity related to a trial of labor?

OBJECTIVE: The objective of the study was to determine whether a model for predicting vaginal birth after cesarean (VBAC) can also predict the probabilty of morbidity associated with a trial of labor (TOL). STUDY DESIGN: Using a previously published prediction model, we categorized women with 1 prior cesarean by chance of VBAC. Prevalence of maternal and neonatal morbidity was stratfied by probability of VBAC success and delivery approach. RESULTS: Morbidity became less frequent as the predicted chance of VBAC increased among women who underwent TOL (P < .001) but not elective repeat cesarean section (ERCS) (P > .05). When the predicted chance of VBAC was less than 70%, women undergoing a TOL were more likely to have maternal morbidity (relative risk [RR], 2.2; 95% confidence interval [CI], 1.5-3.1) than those who underwent an ERCS; when the predicted chance of VBAC was at least 70%, total maternal morbidity was not different between the 2 groups (RR, 0.8; 95% CI, 0.5-1.2). The results were similar for neonatal morbidity. CONCLUSION: A prediction model for VBAC provides information regarding the chance of TOL-related morbidity and suggests that maternal morbidity is not greater for those women who undergo TOL than those who undergo ERCS if the chance of VBAC is at least 70%.

A randomized, controlled trial of magnesium sulfate for the prevention of cerebral palsy.

BACKGROUND: Research suggests that fetal exposure to magnesium sulfate before preterm birth might reduce the risk of cerebral palsy. METHODS: In this multicenter, placebo-controlled, double-blind trial, we randomly assigned women at imminent risk for delivery between 24 and 31 weeks of gestation to receive magnesium sulfate, administered intravenously as a 6-g bolus followed by a constant infusion of 2 g per hour, or matching placebo. The primary outcome was the composite of stillbirth or infant death by 1 year of corrected age or moderate or severe cerebral palsy at or beyond 2 years of corrected age. RESULTS: A total of 2241 women underwent randomization. The baseline characteristics were similar in the two groups. Follow-up was achieved for 95.6% of the children. The rate of the primary outcome was not significantly different in the magnesium sulfate group and the placebo group (11.3% and 11.7%, respectively; relative risk, 0.97; 95% confidence interval [CI], 0.77 to 1.23). However, in a prespecified secondary analysis, moderate or severe cerebral palsy occurred significantly less frequently in the magnesium sulfate group (1.9% vs. 3.5%; relative risk, 0.55; 95% CI, 0.32 to 0.95). The risk of death did not differ significantly between the groups (9.5% vs. 8.5%; relative risk, 1.12; 95% CI, 0.85 to 1.47). No woman had a life-threatening event. CONCLUSIONS: Fetal exposure to magnesium sulfate before anticipated early preterm delivery did not reduce the combined risk of moderate or severe cerebral palsy or death, although the rate of cerebral palsy was reduced among survivors. (ClinicalTrials.gov number, NCT00014989.)

The effect of body mass index on therapeutic response to bacterial vaginosis in pregnancy.

Our objective was to determine the effect of body mass index (BMI) on response to bacterial vaginosis (BV) treatment. A secondary analysis was conducted of two multicenter trials of therapy for BV and TRICHOMONAS VAGINALIS. Gravida were screened for BV between 8 and 22 weeks and randomized between 16 and 23 weeks to metronidazole or placebo. Of 1497 gravida with asymptomatic BV and preconceptional BMI, 738 were randomized to metronidazole; BMI was divided into categories: < 25, 25 to 29.9, and > or = 30. Rates of BV persistence at follow-up were compared using the Mantel-Haenszel chi square. Multiple logistic regression was used to evaluate the effect of BMI on BV persistence at follow-up, adjusting for potential confounders. No association was identified between BMI and BV rate at follow-up ( P = 0.21). BMI was associated with maternal age, smoking, marital status, and black race. Compared with women with BMI of < 25, adjusted odds ratio (OR) of BV at follow-up were BMI 25 to 29.9: OR, 0.66, 95% CI 0.43 to 1.02; BMI > or = 30: OR, 0.83, 95% CI 0.54 to 1.26. We concluded that the persistence of BV after treatment was not related to BMI.

Bone metabolism in pregnant women exposed to single compared with multiple courses of corticosteroids.

OBJECTIVE: To compare markers of maternal bone metabolism between women who received a single compared with multiple courses of antenatal corticosteroids. METHODS: This is an analysis of serum samples from a previously reported randomized, placebo-controlled, multicenter trial. Women at risk for preterm delivery after an initial course of corticosteroids were randomly assigned to weekly courses of betamethasone (active) or placebo. Serum levels of carboxy terminal propeptide of type I procollagen (PICP) and cross-linked carboxy terminal telopeptide of type I collagen (ICTP) were measured to assess the rate of bone formation and resorption, respectively, at three time points. The placebo group (n=93) was compared with the active group, receiving four or more courses of betamethasone (n=112). RESULTS: There were significant (P<.001) increases in PICP and ICTP between baseline and delivery in both groups. Cross-linked carboxy terminal telopeptide of type I collagen, but not PICP, was lower with corticosteroid exposure immediately before administration of the fourth study course (P<.001). No significant differences in PICP and ICTP were seen between groups at delivery. CONCLUSION: Increasing levels of PICP and ICTP with advancing gestation are consistent with physiologic changes in maternal bone metabolism. Multiple courses of corticosteroids for fetal maturation are not associated with persistent or cumulative effects on maternal bone metabolism as measured by PICP and ICTP. LEVEL OF EVIDENCE: II.

Salivary progesterone and estriol among pregnant women treated with 17-alpha-hydroxyprogesterone caproate or placebo.

OBJECTIVE: The objectives of the study was to determine whether salivary progesterone (P) or estriol (E3) concentration at 16-20 weeks' gestation predicts preterm birth or the response to 17alpha-hydroxyprogesterone caproate (17OHPC) and whether 17OHPC treatment affected the trajectory of salivary P and E3 as pregnancy progressed. STUDY DESIGN: This was a secondary analysis of a clinical trial of 17OHPC to prevent preterm birth. Baseline saliva was assayed for P and E3. Weekly salivary samples were obtained from 40 women who received 17OHPC and 40 who received placebo in a multicenter randomized trial of 17OHPC to prevent recurrent preterm delivery. RESULTS: Both low and high baseline saliva P and E3 were associated with a slightly increased risk of preterm birth. However, 17OHPC prevented preterm birth comparably, regardless of baseline salivary hormone concentrations. 17OHPC did not alter the trajectory of salivary P over pregnancy, but it significantly blunted the rise in salivary E3 as well as the rise in the E3/P ratio. CONCLUSION: 17OHPC flattened the trajectory of E3 in the second half of pregnancy, suggesting that the drug influences the fetoplacental unit.

Prediction of uterine rupture associated with attempted vaginal birth after cesarean delivery.

OBJECTIVE: The purpose of this study was to develop a model that predicts individual-specific risk of uterine rupture during an attempted vaginal birth after cesarean delivery. STUDY DESIGN: Women with 1 previous low-transverse cesarean delivery who underwent a trial of labor with a term singleton were identified in a concurrently collected database of deliveries that occurred at 19 academic centers during a 4-year period. We analyzed different classification techniques in an effort to develop an accurate prediction model for uterine rupture. RESULTS: Of the 11,855 women who were available for analysis, 83 women (0.7%) had had a uterine rupture. The optimal final prediction model, which was based on a logistic regression, included 2 variables: any previous vaginal delivery (odds ratio, 0.44; 95% CI, 0.27-0.71) and induction of labor (odds ratio, 1.73; 95% CI, 1.11-2.69). This model, with a c-statistic of 0.627, had poor discriminating ability and did not allow the determination of a clinically useful estimate of the probability of uterine rupture for an individual patient. CONCLUSION: Factors that were available before or at admission for delivery cannot be used to predict accurately the relatively small proportion of women at term who will experience a uterine rupture during an attempted vaginal birth after cesarean delivery.

Previous preterm cesarean delivery and risk of subsequent uterine rupture.

OBJECTIVE: To determine if women with a history of a previous preterm cesarean delivery experienced an increased risk of subsequent uterine rupture compared with women who had a previous nonclassic term cesarean delivery. METHODS: A prospective observational study was performed in singleton gestations that had a previous nonclassic cesarean delivery from 1999 to 2002. Women with a history of a previous preterm cesarean delivery were compared with women who had a previous term cesarean delivery. Women who had both a preterm and term cesarean delivery were included in the preterm group. RESULTS: A prior preterm cesarean delivery was significantly associated with an increased risk of subsequent uterine rupture (0.58% compared with 0.28%, P<.001). When women who had a subsequent elective cesarean delivery were removed (remaining n=26,454) women with a previous preterm cesarean delivery were still significantly more likely to sustain a uterine rupture (0.79% compared with 0.46%, P=.001). However, when only women who had a subsequent trial of labor were included, there was still an absolute increased risk of uterine rupture, but it was not statistically significant (1.00% compared with 0.68%, P=.081). In a multivariable analysis controlling for confounding variables (oxytocin use, two or more previous cesarean deliveries, a cesarean delivery within the past 2 years, and preterm delivery in the current pregnancy), patients with a previous preterm cesarean delivery remained at an increased risk of subsequent uterine rupture (P=.043, odds ratio 1.6, 95% confidence interval 1.01-2.50) compared with women with previous term cesarean delivery. CONCLUSION: Women who have had a previous preterm cesarean delivery are at a minimally increased risk for uterine rupture in a subsequent pregnancy when compared with women who have had previous term cesarean deliveries.

Labor outcomes with increasing number of prior vaginal births after cesarean delivery.

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.

Maternal-Fetal Medicine Units Network cesarean registry: impact of shift change on cesarean complications.

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.

Pregnancy outcomes for women with placenta previa in relation to the number of prior cesarean deliveries.

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.

The relationship between resolution of asymptomatic bacterial vaginosis and spontaneous preterm birth in fetal fibronectin-positive women.

OBJECTIVE: The purpose of this study was to determine the impact of persistent bacterial vaginosis (BV) on the occurrence of spontaneous preterm birth (SPB) in women who test positive for fetal fibronectin. STUDY DESIGN: This is a secondary analysis of a subset of pregnant women who tested positive for BV and fetal fibronectin between 16(0/7) and 25(6/7) weeks of gestation and who participated in randomized placebo controlled trials of antibiotic therapy. Nugent's criteria were used for the diagnosis of BV. Patients were reassessed for the presence of BV after treatment. The rate of SPB at <34 weeks of gestation was analyzed on the basis of treatment mode and BV status at the follow-up visit. RESULTS: The primary studies included a total of 3285 women. A subset of 215 women met the criteria for this analysis. Seventy-seven of 100 patients (77%) in the antibiotics group vs 33 of the 115 patients (28.7%) in the placebo group became BV negative (P < .0001). The rate of SPB at <34 weeks of gestation was lower for BV resolution compared with persistent BV (0 vs 5.7%, respectively; P = .01). CONCLUSION: In women who tested positive for fetal fibronectin and BV, resolution of BV is associated with less SPB before 34 weeks of gestation.

Risk of uterine rupture and adverse perinatal outcome at term after cesarean delivery.

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.

Trial of labor after one previous cesarean delivery for multifetal gestation.

OBJECTIVE: To estimate success rates and risks with a trial of labor after one previous cesarean delivery for multifetal gestation compared with one previous cesarean delivery for a singleton pregnancy. METHODS: Patients from the National Institute of Child Health and Human Development Maternal Fetal Medicine Units Network Cesarean Registry with one previous cesarean delivery and a current term singleton pregnancy were identified. Cases had one previous cesarean delivery for a multifetal pregnancy. Controls had one previous cesarean delivery for a singleton pregnancy. RESULTS: Of cases, 556 of 944 (58.9%) attempted a trial of labor. Of controls, 13,923 of 29,329 (47.5%) attempted a trial of labor. The trial of labor success rate was 85.6% among cases and 73.1% among controls (odds ratio 2.19, 95% confidence interval 1.72-2.78). Compared with trial of labor controls, cases had no statistically increased risk of transfusion, endometritis, intensive care unit admissions, uterine rupture, or perinatal complications. Cases in this analysis with a successful trial of labor were more likely to have previously had a successful vaginal birth after cesarean (37.1% compared with 14.1%, P<.001). CONCLUSION: Women with one previous cesarean delivery for a multifetal gestation have high trial of labor success rates and low complication rates.

Perioperative morbidity and mortality among human immunodeficiency virus infected women undergoing cesarean delivery.

OBJECTIVE: To determine whether human immunodeficiency virus (HIV)-infected women have a higher rate of postcesarean morbidity and mortality compared with women without HIV infection. METHODS: A secondary analysis was performed of women with singleton gestations undergoing cesarean delivery with known HIV status. Data were collected as part of a prospective 4-year (1999-2002) observational study and analyzed using logistic regression. Women were surveyed for a large number of intraoperative complications, common perioperative morbidities, and uncommon maternal complications. RESULTS: There were 378 HIV-infected and 54,281 uninfected women who met criteria. Patients infected with HIV were more likely to have postpartum endometritis (11.6% compared with 5.8%, P<.001), require a postpartum blood transfusion (4.0% compared with 2.0%, P=.02), develop maternal sepsis (1.1% compared with 0.2%, P<.001), be treated for pneumonia (1.3% compared with 0.3%, P=.001), and to have a maternal death (0.8% compared with 0.1%, P<.001). After controlling for potential confounders, patients with HIV infection were more likely to have one or more postpartum morbidities (odds ratio 1.6, 95% confidence interval 1.2-2.2). CONCLUSION: Women with HIV infection undergoing cesarean delivery are at increased risk for perioperative morbidity and maternal mortality. LEVEL OF EVIDENCE: II.

Development of a nomogram for prediction of vaginal birth after cesarean delivery.

OBJECTIVE: To develop a model based on factors available at the first prenatal visit that predicts chance of successful vaginal birth after cesarean delivery (VBAC) for individual patients who undergo a trial of labor. METHODS: All women with one prior low transverse cesarean who underwent a trial of labor at term with a vertex singleton gestation were identified from a concurrently collected database of deliveries at 19 academic centers during a 4-year period. Using factors identifiable at the first prenatal visit, we analyzed different classification techniques in an effort to develop a meaningful prediction model for VBAC success. After development and cross-validation, this model was represented by a graphic nomogram. RESULTS: Seven-thousand six hundred sixty women were available for analysis. The prediction model is based on a multivariable logistic regression, including the variables of maternal age, body mass index, ethnicity, prior vaginal delivery, the occurrence of a VBAC, and a potentially recurrent indication for the cesarean delivery. After analyzing the model with cross-validation techniques, it was found to be both accurate and discriminating. CONCLUSION: A predictive nomogram, which incorporates six variables easily ascertainable at the first prenatal visit, has been developed that allows the determination of a patient-specific chance for successful VBAC for those women who undertake trial of labor. LEVEL OF EVIDENCE: II.

Comparison of maternal and infant outcomes from primary cesarean delivery during the second compared with first stage of labor.

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.

Outcomes of induction of labor after one prior cesarean.

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.