Early vs expectant artificial rupture of membranes following Foley catheter ripening: a randomized controlled trial

Abstract

Background: Early amniotomy shortens the duration of spontaneous labor, yet there is no clear evidence on the optimal timing of amniotomy following cervical ripening. There are limited high-quality studies on the use of early amniotomy intervention following labor induction.

Objective: This study aimed to evaluate whether amniotomy within 1 hour of Foley catheter expulsion reduces the duration of labor among individuals undergoing combined misoprostol and Foley catheter labor induction at term.

Study design: This was a randomized clinical trial conducted from November 2020 to May 2021 comparing amniotomy within 1 hour of Foley catheter expulsion (early artificial rupture of membranes) with expectant management. Randomization was stratified by parity. Labor management was standardized among participants. Individuals undergoing induction at ≥37 weeks with a singleton gestation and needing cervical ripening were eligible. Our primary outcome was time to delivery. Wilcoxon rank sum, Pearson chi-square, and Cox survival analyses with intent-to-treat principles were performed adjusting for age, body mass index, parity, mode of delivery, Bishop score, and the interaction between randomization group and parity. A sample size of 160 was planned to detect a 4-hour reduction in delivery time.

Results: A total of 160 patients (79 early artificial rupture of membranes, 81 expectant management) were randomized. Early artificial rupture of membranes achieved a faster median time to delivery than expectant management (early artificial rupture of membranes: 11.1 hours; interquartile range, 6.25-17.1 vs expectant management: 19.8 hours; interquartile range, 13.2-26.2; P<.001). A greater percentage of individuals in the early artificial rupture of membranes group delivered within 24 hours (86% vs 70%; P=.03). There was no difference in the cesarean delivery rate between the 2 groups (22% vs 31%; P=.25). Individuals delivered 2.3 times faster following early artificial rupture of membranes (hazard ratio, 2.3; 95% confidence interval, 1.5-3.4; P<.001). There were no significant differences in maternal and neonatal outcomes.

Conclusion: Amniotomy within 1 hour of Foley catheter expulsion resulted in 2.3 times faster delivery than expectant management. Therefore, early artificial rupture of membranes should be considered in individuals undergoing mechanical cervical ripening at term.

Trial registration: ClinicalTrials.gov NCT04496908.

Keywords: amniotomy; cervical Foley; labor induction; vaginal.