Outcomes of Elective Induction of Labor versus Expectant Management among Obese Women at ≥39 Weeks.

Maternal obesity is associated with many adverse obstetric outcomes including cesarean delivery. It is unclear whether induction of labor can reduce these risks. Previous studies report conflicting results on the outcomes of elective induction of labor among obese women. This study aimed to compare maternal and neonatal outcomes between obese women undergoing elective induction of labor and those undergoing expectant management at ≥39 weeks. This was a retrospective cohort study from the Consortium on Safe Labor of obese women (defined by prepregnancy body mass index≥ 30kg/m2) with singleton gestations at ≥39 weeks without medical comorbidities from 2002 through 2008. Women scheduled for medically indicated induction of labor were excluded. The primary outcome of cesarean delivery was compared between obese women undergoing elective induction of labor and expectant management during 39th, 40th, and 41st weeks using univariable and multivariable analyses, stratifying by parity. In all, 7,298 nulliparous and 9,789 parous women were eligible for analysis. After controlling for potential confounders, elective induction of labor during 39th week in nulliparous and parous women was associated with lower odds of cesarean delivery (39.1 vs. 41.6%, adjusted odds ratio [OR]: 0.47, 95% confidence interval [CI]: 0.30-0.74 for nulliparous and 5.5 vs. 10.1%, adjusted OR: 0.34, 95% CI: 0.20-0.61 for parous women) compared with expectant management. Elective induction of labor during 40th and 41st weeks was not associated with lower odds of cesarean delivery. In addition, macrosomia was reduced in nulliparous women undergoing elective induction of labor during the 40th week (12.1 vs. 18.5%, adjusted OR: 0.56, 95% CI: 0.35-0.87) and in parous women undergoing elective induction of labor during 39th (11.6 vs. 17.6%, adjusted OR: 0.50, 95% CI: 0.38-0.66) and 40th weeks (16.4 vs. 22.2%, adjusted OR: 0.53, 95% CI: 0.36-0.78). Elective induction of labor at 39 weeks, when compared with expectant management, was associated with lower cesarean deliveries in obese nulliparous and parous women.

Palatnik A ，Kominiarek MA 《-》

Nonmedically indicated induction in morbidly obese women is not associated with an increased risk of cesarean delivery.

The prevalence of morbid obesity (body mass index ≥40 kg/m2) in women aged 20-39 years was 7.5% in 2009 through 2010. Morbid obesity is associated with an increased risk of stillbirth compared with normal body mass index, especially >39 weeks' gestation. The data regarding increased risk of cesarean delivery associated with nonmedically indicated induction of labor compared to expectant management in morbidly obese women are limited. We sought to compare the cesarean delivery rate of nonmedically indicated induction of labor with expectant management in morbidly obese women without other comorbidity. This was a retrospective cohort study from the Consortium on Safe Labor of morbidly obese women with singleton, cephalic gestations without previous cesarean, chronic hypertension, or gestational or pregestational diabetes between 37 0/7 and 41 6/7 weeks' gestation. We examined maternal outcomes including cesarean delivery, operative delivery, third- or fourth-degree laceration, postpartum hemorrhage, and composite maternal outcome (any of: transfusion, intensive care unit admission, venous thromboembolism). We also examined neonatal outcomes including shoulder dystocia, macrosomia (>4000 g), neonatal intensive care unit admission, and composite neonatal outcome (5-min Apgar score <5, stillbirth, neonatal death, or asphyxia or hypoxic-ischemic encephalopathy). Adjusted odds ratios with 95% confidence intervals were calculated, controlling for maternal characteristics, hospital type, and simplified Bishop score. Analyses were conducted at early and full term (37 0/7 to 38 6/7 and 39 0/7 to 40 6/7 weeks' gestation, respectively). Women who delivered between 41 0/7 and 41 6/7 weeks' gestation were included as expectant management group. Of 1894 nulliparous and 2455 multiparous morbidly obese women, 429 (22.7%) and 791 (32.2%) had nonmedically indicated induction, respectively. In nulliparas, nonmedically indicated induction was not associated with increased risks of cesarean delivery and was associated with decreased risks of macrosomia (2.2% vs 11.0%; adjusted odds ratio, 0.24; 95% confidence interval, 0.05-0.70) at early term and decreased neonatal intensive care unit admission (5.1% vs 8.9%; adjusted odds ratio, 0.59; 95% confidence interval, 0.33-0.98) at full term compared with expectant management. In multiparas, nonmedically indicated induction compared with expectant management was associated with a decreased risk of macrosomia at early term (4.2% vs 14.3%; adjusted odds ratio, 0.30; 95% confidence interval, 0.13-0.60), cesarean delivery at full term (5.4% vs 7.9%; adjusted odds ratio, 0.64; 95% confidence interval, 0.41-0.98), and composite neonatal outcome (0% vs 0.6%; adjusted odds ratio, 0.10; 95% confidence interval, <.01-0.89) at full term. In morbidly obese women without other comorbidity, nonmedically indicated induction was not associated with an increased risk of cesarean delivery.

Kawakita T ，Iqbal SN ，Huang CC ，Reddy UM ... -  《-》

Term Elective Induction of Labor and Pregnancy Outcomes Among Obese Women and Their Offspring.

Gibbs Pickens CM ，Kramer MR ，Howards PP ，Badell ML ，Caughey AB ，Hogue CJ ... -  《-》

Maternal and newborn outcomes with elective induction of labor at term.

A growing body of evidence supports improved or not worsened birth outcomes with nonmedically indicated induction of labor at 39 weeks gestation compared with expectant management. This evidence includes 2 recent randomized control trials. However, concern has been raised as to whether these studies are applicable to a broader US pregnant population. Our goal was to compare outcomes for electively induced births at ≥39 weeks gestation with those that were not electively induced. We conducted a retrospective cohort study using chart-abstracted data on births from January 1, 2012, to December 31, 2017, at 21 hospitals in the Northwest United States. The study was restricted to singleton cephalic hospital births at 39+0-42+6 weeks gestation. Exclusions included previous cesarean birth, missing data for delivery type or gestational week at birth, antepartum stillbirth, cesarean birth without any attempt at vaginal birth, fetal anomaly, gestational diabetes mellitus, prepregnancy diabetes mellitus, and prepregnancy hypertension. The rate of cesarean birth for elective inductions at both 39 and 40 weeks gestation was compared with the rate in all other on-going pregnancies in the same gestational week. Maternal outcomes (operative vaginal birth, shoulder dystocia, 3rd- or 4th-degree perineal laceration, pregnancy-related hypertension, and postpartum hemorrhage) and newborn infant outcomes (macrosomia, 5-minute Apgar <7, resuscitation at delivery, intubation, respiratory complications, and neonatal intensive care unit admission) were also compared between elective inductions and on-going pregnancies at 39 and 40 weeks gestation. Logistic regression modeling was used to produce odds ratios for outcomes with adjustment for maternal age and body mass index. Results were stratified by parity and gestational week at birth. Duration of hospital stay (admission to delivery, delivery to discharge, and total stay) were compared between elective inductions and on-going pregnancies. A total of 55,694 births were included in the study cohort: 4002 elective inductions at ≥39+0 weeks gestation and 51,692 births at 39+0-42+6 weeks gestation that were not electively induced. In nulliparous women, elective induction at 39 weeks gestation was associated with a decreased likelihood of cesarean birth (14.7% vs 23.2%; adjusted odds ratio, 0.61; 95% confidence interval, 0.41-0.89) and an increased rate of operative vaginal birth (18.5% vs 10.8%; adjusted odds ratio, 1.8; 95% confidence interval, 1.28-2.54) compared with on-going pregnancies. In multiparous women, cesarean birth rates were similar in the elective inductions and on-going pregnancies. Elective induction at 39 weeks gestation was associated with a decreased likelihood of pregnancy-related hypertension in nulliparous (2.2% vs 7.3%; adjusted odds ratio, 0.28; 95% confidence interval, 0.11-0.68) and multiparous women (0.9% vs 3.5%; adjusted odds ratio, 0.24; 95% confidence interval, 0.15-0.38). Term elective induction was not associated with any statistically significant increase in adverse newborn infant outcomes. Elective induction of labor at 39 weeks gestation was associated with increased time from admission to delivery for both nulliparous (1.3 hours; 95% confidence interval, 0.2-2.3) and multiparous women (3.4 hours; 95% confidence interval, 3.2-3.6). Elective induction of labor at 39 weeks gestation is associated with a decrease in cesarean birth in nulliparous women, decreased pregnancy-related hypertension in multiparous and nulliparous women, and increased time in labor and delivery. How to use this information remains the challenge.

Souter V ，Painter I ，Sitcov K ，Caughey AB ... -  《-》

Elective induction of labor at 39 weeks compared with expectant management: a meta-analysis of cohort studies.

Elective induction of labor at 39 weeks among low-risk nulliparous women has reduced the chance of cesarean and other adverse maternal and perinatal outcomes in a randomized trial, although its clinical effectiveness in nonresearch settings remains uncertain. To perform a systematic review of observational studies that compared elective induction of labor at 39 weeks among nulliparous women with expectant management and to use meta-analytic techniques to estimate the association of elective induction with cesarean delivery, as well as other maternal and perinatal outcomes. Studies were eligible for this meta-analysis only if they: (1) were observational; (2) compared women undergoing labor induction at 39 weeks with women undergoing expectant management beyond that gestational age; (3) included women in the induction group only if they had no other indication for labor induction at 39 weeks; and (4) provided data specifically for nulliparous women. The predefined primary outcome was cesarean delivery, and secondary outcomes representing other maternal and perinatal morbidities also were evaluated. Outcome data from different studies were combined to estimate pooled relative risks with 95% confidence intervals using random-effects models. Of 375 studies identified by the initial search, 6 cohort studies, which included 66,019 women undergoing elective labor induction at 39 weeks and 584,390 undergoing expectant management, met inclusion criteria. Elective induction of labor at 39 weeks was associated with a significantly lower frequency of cesarean delivery (26.4% vs 29.1%; relative risk, 0.83; 95% confidence interval, 0.74-0.93), as well as of peripartum infection (2.8% vs 5.2%; relative risk, 0.53; 95% confidence interval, 0.39-0.72). Neonates of women in the induction group were less likely to have respiratory morbidity (0.7% vs 1.5%; relative risk, 0.71; 95% confidence interval, 0.59-0.85); meconium aspiration syndrome (0.7% vs 3.0%; relative risk, 0.49; 95% confidence interval, 0.26-0.92); and neonatal intensive care unit admission (3.5% vs 5.5%; relative risk, 0.80; 95% confidence interval, 0.72-0.88). There also was a lower risk of perinatal mortality (0.04% vs 0.2%; relative risk, 0.27; 95% confidence interval, 0.09-0.76). This meta-analysis of 6 cohort studies demonstrates that elective induction of labor at 39 weeks, compared with expectant management beyond that gestational age, was associated with a significantly lower risk of cesarean delivery, maternal peripartum infection, and perinatal adverse outcomes, including respiratory morbidity, intensive care unit admission, and mortality.

Grobman WA ，Caughey AB 《-》