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 + 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 E 2 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.

Induction of labour in an out patient setting?

“…Therefore in summary we concluded that: two doses of 25 g OM administered four hours apart, was inadequate and inferior to a supra cervical Foley catheter for pre induction cervical ripening in post dated pregnancies 42 compared to a supra cervical Foley catheter for 24 hours, three doses of OM 50 g four hourly was more effective for cervical ripening and even resulted in IOL 43 , and three doses of OM 50 µg given four hourly per day for 48 hours was feasible and more effective than a supra cervical Foley catheter for 48 hours, for IOL 44 .…”

“…The hourly dosing regimen has been calculated according to the pharmokinetics of OM where its half-life as well as the time taken to achieve peak serum concentrations has been estimated to vary from approximately 20-40 mins respectively 25,37 . Although doses of 20, 40 and 60 µg of OM are easily prepared by dissolving the commonly available 200 µg tablet in 200 ml of water, 25 µg tablets are also now available, and a more practical regimen of 50 µg administered four hourly, could be implemented 22,26,43,44 . This would be useful in settings with a heavy work load and lacking facilities for one to one nursing care and intensive fetal monitoring.…”

“…In all three RCT, although the patients could not be blinded to the interventions, the investigators and the analysts of the results were blinded with regard to the intervention. Similar methods were used in all three RCT [42][43] .…”

“…The objective was to compare three doses of OM 50 µg four hourly versus a supra cervical Foley catheter for 24 hours, for pre-induction cervical ripening. This study involved 180 women who were allocated to receive three doses of OM 50 µg four hourly (n=91) or a supra cervical Foley catheter for 24 hours (n=89 Conclusions: Compared to a supra cervical Foley catheter for 24 hours, three doses of OM 50 µg four hourly was more effective for cervical ripening and even resulted in IOL 43 .…”

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“…11 Currently, prostaglandins are considered the most effective method (delivery before 24hours). 12,13 Other alternatives such as mechanical methods (Foley catheter, double balloon intracervical catheter) have also demonstrated efficacy and safety for IOL. [14][15][16] Multiple prostaglandin regimens have been shown to improve unfavourable cervix.…”