Term elective induction of labour and perinatal outcomes in obese women: retrospective cohort study

Abstract

Objective To compare perinatal outcomes between elective induction of labor (eIOL) and expectant management in obese women. Design Retrospective cohort study. Setting Deliveries in California in 2007. Population Term, singleton, vertex, nonanomalous deliveries among obese women (n=74,725). Methods Women who underwent eIOL at 37 weeks were compared with women who were expectantly managed at that gestational age. Similar comparisons were made at 38, 39, and 40 weeks. Results were stratified by parity. Chi-square tests and multivariable logistic regression were used for statistical comparison. Main Outcome Measures Method of delivery, severe perineal lacerations, postpartum hemorrhage, chorioamnionitis, macrosomia, shoulder dystocia, brachial plexus injury, respiratory distress syndrome. Results The odds of cesarean delivery were lower among nulliparous women with eIOL at 37 weeks (odds ratio [OR] 0.55, 95% confidence interval [CI] 0.34–0.90) and 39 weeks (OR 0.77, 95% CI 0.63–0.95) compared to expectant management. Among multiparous women with a prior vaginal delivery, eIOL at 37 (OR 0.39, 95% CI 0.24–0.64), 38 (OR 0.65, 95% CI 0.51–0.82), and 39 weeks (OR 0.67, 95% CI 0.56–0.81) was associated with lower odds of cesarean. Additionally, eIOL at 38, 39, and 40 weeks was associated with lower odds of macrosomia. There were no differences in the odds of operative vaginal delivery, lacerations, brachial plexus injury, or respiratory distress syndrome. Conclusions In obese women, term eIOL may decrease the risk of cesarean delivery, particularly in multiparas, without increasing the risks of other adverse outcomes when compared with expectant management. Tweetable Abstract Elective induction of labor in obese women does not increase risk of cesarean or other perinatal morbidities.

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

“…24 Since birth weight increases with gestational age, it is understandable that elective induction of labor was associated with a decreased risk of macrosomia compared with expectant management in our study. Consistent with a previous study of obese women, 23 our study did not demonstrate increased neonatal morbidities associated with non-medically indicated induction of labor compared with expectant management. Non-medically indicated induction of labor at full term was associated with a decreased risk of NICU admission in nulliparous women and composite neonatal outcome in multiparous women.…”

“…Our study was different from previous studies since we only included morbidly obese women without other comorbidity. Similar to previous studies of the obese population, 14, 23 our study did not show an increased risk of maternal complications associated with non-medically indicated induction of labor compared with expectant management, although our study had limited power to detect a difference in rare but severe maternal complications.…”

“…14 However, Lee et al in 2015 conducted a retrospective study of 74,725 obese women (BMI ≥30 kg/m 2 ) using an administrative database, which showed elective induction of labor at 39 weeks' gestation was associated with a decreased risk of cesarean delivery compared with expectant management in both nulliparuous and multiparous women. 23 In our study of morbidly obese women without other comorbidity, the risk of cesarean delivery associated with non-medically indicated induction of labor was similar in nulliparous women at both early term and full term. Our study was different from previous studies since we only included morbidly obese women without other comorbidity.…”

“…20, 21, 22 In obese women, data regarding the association between cesarean delivery and non-medically indicated induction of labor are conflicting. 14, 23 Wolfe et al in 2014 conducted a retrospective study of 410 obese nulliparous women (BMI ≥30 kg/m 2 ) with an unfavorable cervix, which showed elective induction of labor between 39 and 40 weeks' gestation was associated with an increased risk of cesarean delivery compared with expectant management. 14 However, Lee et al in 2015 conducted a retrospective study of 74,725 obese women (BMI ≥30 kg/m 2 ) using an administrative database, which showed elective induction of labor at 39 weeks' gestation was associated with a decreased risk of cesarean delivery compared with expectant management in both nulliparuous and multiparous women.…”

“…23 Morbid obesity is a known risk factor for higher birth weight. 24 Since birth weight increases with gestational age, it is understandable that elective induction of labor was associated with a decreased risk of macrosomia compared with expectant management in our study.…”