Abstract

Objective To compare the safety of misoprostol vaginal insert (MVI) for labor induction using standard and adjusted criteria. Methods This was a single-center, comparative cohort study of 138 pregnant women ≥37/0 weeks undergoing labor induction with MVI using standard (69 women; administration for up to 24 h; MVI-24) or adjusted (69 women; administration for up to 10 h; MVI-10) criteria in a tertiary academic center in Germany. The main maternal safety outcomes were the rate of tachysystole and rate of tachysystole requiring tocolysis. Neonatal safety assessments included Apgar score at 5 min and postpartum arterial fetal pH. Results Uterine tachysystole occurred in more women in the MVI-24 group compared with the MVI-10 group [47.8% vs. 25.5%; P = 0.001; relative risk (RR) 2.36 (95% confidence interval [CI]: 1.39-4.00)] and as did uterine tachysystole requiring tocolysis [MVI-24: 26.1% vs. MVI-10: 11.6%; P = 0.049; RR 2.25 (95% CI: 1.05-4.83)]. The mean 5-min Apgar scores were 9.64 for the MVI-24 group and 9.87 for the MVI-10 (P = 0.016). Low postpartum umbilical arterial pH values occurred more often in the MVI-24 compared with the MVI-10 group (pH 7.10-7.19: 26.1% vs. 20.3% and pH <7.10: 4.4% vs. 0.0%, respectively). Conclusion Adjusted retrieval criteria for MVI of up to 10 h exposure instead of the standard 24 h reduced uterine tachysystole and improved the neonatal outcome.