428. Trials in low-resource settings: the INFORM study (oral misoprostol versus balloon induction in women with PIH or pre-eclampsia)

Abstract

Between 62,000 and 77,000 women die annually from pre-eclampsia/eclampsia. Prompt delivery, preferably by the vaginal route, is vital for good maternal and neonatal outcomes. Two low cost interventions -low dose oral misoprostol tablets and transcervical Foley catheterisation- are already used in low resource settings. In this open label, parallel randomised study, our objective was to compare their relative risks and benefits. 602 women with a live fetus requiring delivery for pre-eclampsia or hypertension were randomly assigned to labour induction with oral misoprostol 25 micrograms every 2 h (maximum of 12 doses) or a transcervical Foley catheter (size 18 F with 30 ml balloon) which remained until active labour started, the Foley catheter fell out, or 12 h elapsed. Randomisation was computer-generated with allocation concealment by opaque sequentially numbered sealed envelopes. Induction continued with artificial membrane rupture and oxytocin, administered through a micro-drip gravity infusion set. Fetal monitoring was by intermittent auscultation. The primary outcome was vaginal birth within 24 h, and trial registration as with ClinicalTrials.gov (NCT01801410). 302 women were allocated to misoprostol and 300 women to Foley catheter; all were analysed. More women in the misoprostol arm had a vaginal birth within 24 h (57.0% vs. 47.0%; absolute risk difference (RD) 10.0%, with 95%CI 2.0% to 17.9%). Rates of uterine hyperstimulation were very low in both groups (0.7% vs 0.3%; RD 0.3%; −0.8% to 1.5%) and no differences were seen in neonatal morbidity. More women in the misoprostol group would use the same method in the future should they require another induction (82.8% vs. 72.0%; RD 10.8%; 4.2% to 17.4%). Oral misoprostol 25 micrograms was more effective and more acceptable to women than a transcervical Foley catheter for induction of labour in women requiring delivery because of pre-eclampsia or hypertension. MRC/DFID/Wellcome Trust Joint Global Health Trials Scheme (Ref. G1100686/1).