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, randomized controlled trial conducted in 180 consecutive women with singleton uncomplicated pregnancies with Modified Bishop Score (MBS) <5 at 40 weeks + 6days 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