Three doses of oral misoprostol versus an intra-cervical Foley catheter for 24 hours for pre-induction cervical ripening in post- dated pregnancies: a randomized controlled trial

Abstract

Objectives: To compare three doses of oral misoprostol 50μg four hourly versus an intra-cervical Foley catheter for 24 hours, for pre-induction cervical ripening.

Methods: Primary investigator blinded, randomised controlled trial conducted in 180 consecutive women with singleton uncomplicated pregnancies with Modified Bishop Score (MBS) 5 at 40 weeks + 6 days gestation, allocated by stratified (primigravida / multigravida) block randomization to receive three doses of oral misoprostol 50μg four hourly or an intra-cervical Foley catheter for 24 hours. MBS reassessed at 41 weeks gestation. If MBS 7, induction of labour (IOL) with amniotomy and intravenous oxytocin infusion. If MBS<7, cross over therapy with intracervical Foley catheter for misoprostol group, vaginal prostaglandin E2 for Foley group.

Results: At commencement, no significant differences in age, parity, body mass index and MBS between the two groups. Greater proportions established labour in both primigravidae (30% vs. 9%; RR=4.4, 95% CI 1.3-14.6; p=0.01) and multigravidae (44%.vs.16%; RR=4.3; 95% CI 1.6-11.8; p=0.003) before 41 weeks of gestation in misoprostol group compared to the Foley group. Among the multigravidae, the mean increase of MBS was greater in the misoprostol group (3.1; 95% CI 2.4-4) compared to the Foley group (2.4; 95% CI 1.9-2.7, p=0.04). One primigravida and two multigravidae developed hyper stimulation after misoprostol therapy. No significant differences in the other maternal and perinatal outcomes.

Conclusions: Compared to an intra-cervical Foley catheter for 24 hours, three doses of oral misoprostol 50μg four hourly was more effective for cervical ripening and even resulted in IOL.