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 ... -  《-》

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 ... -  《-》

Induction of labor before 40 weeks is associated with lower rate of cesarean delivery in women with gestational diabetes mellitus.

In women with gestational diabetes mellitus, it is not clear whether routine induction of labor at <40 weeks of gestation is beneficial to mother and newborn infant. The purpose of this study was to compare outcomes among women with gestational diabetes mellitus who had induction of labor at either 38 or 39 weeks with those whose pregnancy was managed expectantly. We included all women in Ontario, Canada, with diagnosed gestational diabetes mellitus who had a singleton hospital birth at ≥38 + 0 weeks of gestation between April 2012 and March 2014. Data were obtained from the Better Outcomes Registry & Network Ontario, which is a province-wide registry of all births in Ontario, Canada. Women who underwent induction of labor at 38 + 0 to 38 + 6 weeks of gestation (38-IOL; n = 1188) were compared with those who remained undelivered until 39 + 0 weeks of gestation (38-Expectant; n = 5229). Separately, those women who underwent induction of labor at 39 + 0 to 39 + 6 weeks of gestation (39-IOL; n = 1036) were compared with women who remained undelivered until 40 + 0 weeks of gestation (39-Expectant; n = 2162). Odds ratios and 95% confidence intervals were adjusted for maternal age, parity, insulin treatment, and prepregnancy body mass index. Of 281,480 women who gave birth during the study period, 14,600 women (5.2%) had gestational diabetes mellitus; of these, 8392 women (57.5%) met all inclusion criteria. Compared with the 38-Expectant group, those women in the 38-IOL group had lower odds for cesarean delivery (adjusted odds ratio, 0.73; 95% confidence interval, 0.52-0.90), higher odds for neonatal intensive care unit admission (adjusted odds ratio, 1.36; 95% confidence interval, 1.09-1.69), and no difference in other maternal-newborn infant outcomes. Compared with the 39-Expectant group, women in the 39-IOL group likewise had lower odds for cesarean delivery (adjusted odds ratio, 0.73; 95% confidence interval, 0.58-0.93) but no difference in neonatal intensive care unit admission (adjusted odds ratio, 0.83; 95% confidence interval, 0.61-1.11). In women with gestational diabetes mellitus, the routine induction of labor at 38 or 39 weeks is associated with a lower risk of cesarean delivery compared with expectant management but may increase the risk of neonatal intensive care unit admission when done at <39 weeks of gestation.

Melamed N ，Ray JG ，Geary M ，Bedard D ，Yang C ，Sprague A ，Murray-Davis B ，Barrett J ，Berger H ... -  《-》

Outcomes among Nulliparous Women Undergoing Nonmedically Indicated Induction of Labor at 39 Weeks Compared with Expectant Management Differ by Maternal Age.

Prior studies have demonstrated the potential benefit of nonmedically indicated induction of labor for nulliparous women at 39 weeks of gestation, yet few have studied the impact of this management strategy in different maternal age groups on obstetric outcomes. We sought to assess whether obstetric outcomes among women undergoing nonmedically indicated induction of labor at 39 weeks of gestation as compared with expectant management vary based on maternal age. This was a retrospective cohort study of singleton, nonanomalous, deliveries between 2007 and 2012 in California. We defined nonmedically indicated induction of labor as induction of labor without a specific medical indication, and women with planned cesarean sections were excluded. We compared induction of labor with expectant management beyond the gestational age of induction and examined this comparison in different maternal age groups. Numerous maternal and neonatal outcomes were examined. Chi-squared and multivariable logistic regression analyses were used for statistical comparisons and a p-value of less than 0.05 was used to indicate statistical significance. A total of 630,485 women-infant dyads met our inclusion criteria and were included in this study. At 39 weeks' gestation, 6% of women underwent nonmedically indicated induction of labor and 94% underwent expectant management. Women 20 to 34 and ≥35 years old had lower odds of cesarean delivery if they underwent induction of labor. Women of all ages undergoing nonmedically indicated induction of labor had higher odds of operative vaginal delivery. Neonatal outcomes were better with nonmedically indicated induction of labor, including lower odds of neonatal intensive care unit admission and neonatal respiratory distress. Our study demonstrated that obstetric outcomes vary among women undergoing nonmedically indicated induction of labor compared with expectant management when stratified by maternal age. These findings illustrate the importance of understanding age-related differences in outcomes associated with nonmedically indicated induction of labor. · Outcomes are different by age with nonmedically indicated induction of labor (IOL).. · The odds of cesarean delivery with IOL decreases with increasing maternal age compared with expectant management.. · Neonatal outcomes were improved with IOL compared with expectant management..

Hersh AR ，Urbanowicz E ，Garg B ，Schmidt EM ，Packer CH ，Caughey AB ... -  《-》

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 ... -  《-》