Methods of induction of labor in women with obesity: A secondary analysis of two multicenter randomized controlled trials.

INTRODUCTION: Obesity is an increasing public health concern worldwide and can lead to more complications in pregnancy and childbirth. Women with obesity more often require induction of labor for various indications. The aim of this study is to assess which method of induction of labor is safest and most effective in women with obesity. MATERIAL AND METHODS: This is a secondary analysis of two randomized controlled trials about induction of labor. Women with a term singleton pregnancy in cephalic presentation, an unfavorable cervix, intact membranes and without a previous cesarean section were randomly allocated to cervical priming with a Foley catheter or vaginal prostaglandin-E2-gel (PROBAAT-I) or a Foley catheter or oral misoprostol (PROBAAT-II). The inclusion and exclusion criteria for the studies were identical. Induction methods were compared in women with obesity (body mass index ≥30.0). Main outcomes were cesarean section and postpartum hemorrhage (blood loss >1000 mL). RESULTS: A total of 2664 women, were included in the trials, 517 of whom were obese: 254 women with obesity received a Foley catheter, 176 oral misoprostol and 87 prostaglandin E2 (PGE2). A cesarean section was performed in 29.1% of women allocated to Foley vs 22.2% in the misoprostol and 23.0% in the PGE2 groups. Comparisons between groups revealed no statistically significant differences: the relative risk [RR] was 1.31 (95% confidence interval [CI] 0.94-1.84) in the Foley vs misoprostol group and 1.27 (95% CI 0.83-1.95) in the Foley vs PGE2 group. The rates of postpartum hemorrhage were comparable (10.6%, 11.4% and 6.9%, respectively; P = 0.512). In women with obesity, more often a switch to another method occurred in the Foley group, (20.1% vs 6.3% in misoprostol vs 1.1% in the PGE2 group; P < 0.001). The risk of a failed Foley placement was higher in women with obesity than in women without obesity (8.3% vs 3.2%; adjusted odds ratio 3.12, 95% CI 1.65-5.90). CONCLUSIONS: In women with obesity we found a nonsignificant trend towards an increased rate of cesarean sections in the group induced with a Foley catheter compared to oral misoprostol; however, the study lacked power for this subgroup analysis. The finding of a higher risk of failed placement of a Foley catheter in women with obesity can be used in shared decision making.

The influence of various induction methods on adverse outcomes in small for gestational age neonates: A secondary analysis of the PROBAAT 1 and 2 trials.

OBJECTIVE: To evaluate the safety aspects of different induction methods in pregnancies with small-for-gestational-age neonates. STUDY DESIGN: This was a secondary analysis of two previously reported multicenter, randomized controlled trials conducted in the Netherlands. In the original trials, women were randomized to either a 30 cc Foley catheter, vaginal prostaglandin E2 (PROBAAT-1) or oral misoprostol (PROBAAT-2). A total of 425 patients with a term, singleton pregnancy in cephalic presentation with an indication for labor induction and a small-for-gestational-age neonate were included in this secondary analysis. Our primary outcome was a composed adverse neonatal outcome of Apgar score < 7 after 5 min and/or a pH in the umbilical artery < 7.05 and/or NICU admission. Secondary outcomes were mode of birth, operative birth for fetal distress and pH < 7.10 in the umbilical artery. For these outcome measures, multivariate as well as bivariate analyses were performed. RESULTS: An adverse neonatal outcome occurred in 4.7 % (10/214) induction with a Foley catheter, versus 12.8 % (19/149) after misoprostol (RR 0.36; 95 % CI 0.17-0.76) and 4.7 % (3/64) after Prostaglandin E2 (RR 0.98; 95 %CI 0.28-3.51). For individual components of the composed outcome of adverse events, a difference was found between a Foley catheter and misoprostol for Apgar score < 7 at 5 min (0.5 % versus 3.4; RR 0.14; 95 %CI 0.02-1.16) and NICU admission (1.9 % versus 6.1 %; RR 0.31; 0.10-0.97). No differences were found for mode of birth. CONCLUSIONS: For women who gave birth to a small-for-gestational-age neonate, a Foley catheter is probably a safer induction method compared to oral misoprostol.