Intra Cervical Foley Catheter vs oral misoprostol for pre induction cervical ripening of postdated pregnancies

Introduction: An intracervical Foley catheter is a common method used for pre-induction cervical ripening in Sri Lanka. Low dose oral Misoprostol (25 μg 2 hrly) has been recently recommended as a method for ripening of cervix and induction of labour (IOL)

Objectives: To compare the effectiveness of the insertion of an intra-cervical Foley catheter for 24 hrs versus two doses of oral Misoprostol - 25μg four hours apart, in ripening the cervix prior to IOL, in postdated pregnancies.

Methods: A Randomized controlled trial. Women with uncomplicated singleton pregnancies, having a cephalic presentation and a cervix unfavorable for IOL [modified Bishop Score (MBS) < 6] at 40 weeks and 6 days of gestation, were allocated to receive either two doses of oral Misoprostol - 25 μg, four hours apart (n=74) or intracervical Foley Catheter for 24 hrs (n=78), by stratified (primip / multip) block randomization. The following morning all were assessed and their MBS recorded by one of the last three authors, all of whom were blind to the interventions, as other doctors supervised and carried out the interventions. If the cervix was favourable, IOL was carried out with amniotomy and intravenous oxytocin infusion. The method of delivery and induction delivery interval (IDI) were recorded. If spontaneous labour (SOL) was established prior to this assessment, it was recorded.

Results: There were no significant differences in the distribution of parity, and the mean ages and the mean pre intervention MBS in the primigravidae and multigravidae, between the two study groups. There were significant increases in mean MBS (ranging from 2.6 – 3.3 and 95% CIs 1.7- 4.1, p <0.001) after the interventions in both groups. However there was no significant difference between the mean increases of MBS between the groups. In the primigravidae, the mean MBS after 24 hours was greater in the Foley catheter group compared to the misoprostol group (6.9, 95%CI 6.3 – 7.5 vs 5.7, 95% CI 4.8 – 6.7, p < 0.05). There were no significant differences in the proportions of primips and multips establishing SOL. More primips and multips had cervices favourable for IOL in the Foley catheter group compared to the misoprostol group (p < 0.05). There were no significant differences in the mean IDI after IOL; successful vaginal delivery after IOL; and the caesarean section rates between the groups. In the Misoprostol group there were no cases of uterine hyperstimulation, but two women complained of dyspepsia.

Conclusions: Intracervical Foley catheter for 24 hours was better than two doses of 25 μg misoprostol administered orally four hours apart, for pre induction cervical ripening in postdated pregnancies.

DOI: http://dx.doi.org/10.4038/sljog.v36i3.7714

Sri Lanka Journal of Obstetrics and Gynaecology 2014; 36: 66-70