Early versus delayed amniotomy with immediate oxytocin after Foley catheter cervical ripening in multiparous women with labor induction: A randomized controlled trial

Abstract

Objective: To evaluate immediate oxytocin and early amniotomy compared with delayed amniotomy after Foley catheter cervical ripening in multiparous women on intervention-to-delivery interval.

Methods: This randomized trial was conducted in Malaysia in 232 term multiparous women with balloon catheter-ripened cervixes (dilatation ≥3 cm), singleton fetus, cephalic presentation with intact membranes, and reassuring fetal heart rate tracing. They were randomized to immediate titrated intravenous oxytocin infusion and early amniotomy (116) or delayed amniotomy after 4 h of oxytocin (116). Primary outcome was intervention (oxytocin initiation)-to-delivery interval.

Results: Oxytocin-to-delivery intervals were a median of 4.99 h (interquartile range [IQR], 3.21-7.82 h) versus 6.23 h (IQR, 4.50-8.45 h) (P < 0.001) for the early versus delayed amniotomy arms, respectively. Delivery rate at 4 h and 6 h after oxytocin infusion were 40 of 116 (35%) versus 22 of 116 (19%) (relative risk [RR], 1.82 [95% confidence interval (CI), 1.16-2.86], P = 0.011) and 77 of 116 (66%) versus 54 of 116 (47%) (RR, 1.43 [95% CI, 1.13-1.80], P = 0.003) for the early versus delayed amniotomy arms, respectively. Maternal satisfaction on birth process were 7 (IQR, 6-8) versus 7 (IQR, 7-8) (P = 0.006), uterine hyperstimulation rates were 10 of 116 (9%) versus 14 of 116 (12%) (RR, 0.71 [95% CI, 0.33-1.54]) (P = 0.519), and Cesarean delivery rates were 17 of 116 (15%) versus 19 of 116 (16%) (RR, 0.90 [95% CI, 0.49-1.63], P = 0.856) for the early versus delayed amniotomy arms, respectively.

Conclusion: In multiparas at term following cervical ripening by Foley catheter, immediate oxytocin and early amniotomy compared with a scheduled 4-h delay to amniotomy shortens the interval to birth and decreases uterine hyperactivity in labor but lowers maternal satisfaction. The cesarean delivery rate is not significantly reduced.

Clinical trial registration: This study was registered with the International Standard Randomised Controlled Trial Number (ISRCTN) on September 29, 2020, with trial identification number: ISRCTN87066007 (https://doi.org/10.1186/ISRCTN87066007). The first participant was recruited on September 29, 2020, after ISRCTN registry confirmation was received.

Keywords: Foley catheter; cesarean; delayed amniotomy; early amniotomy; labor induction; maternal satisfaction; multipara; oxytocin; oxytocin-to-delivery interval.