Randomized clinical trial between hourly titrated and 2 hourly static oral misoprostol solution for induction of labor

Abstract

Misoprostol is an effective agent for the induction of labor. Existing guidelines recommend oral misoprostol solution 25 μg every 2 hours. However, more research is required to optimize the use of oral misoprostol solution for the induction of labor. The purpose of this study was to compare efficacy and safety of hourly titrated-dose oral misoprostol solution with static-dose oral misoprostol solution every 2 hours for labor induction. In this randomized controlled study, oral misoprostol solution was administered as (1) 20 μg hourly (≤4 doses) that was increased in the absence of regular uterine contractions to 40 μg hourly (≤4 doses) and then to 60 μg hourly (≤16 doses) or (2) 25 μg every 2hours until active labor began (≤12 doses). A sample size of 146 women was planned with the use of a projected 95% rate for the primary endpoint (vaginal delivery within 24 hours) for hourly titrated-dose misoprostol and 80% rate for static-dose misoprostol every 2 hours. Safety outcomes included maternal morbidity and adverse neonatal outcomes. From December 2013 to July 2015, 146 women were assigned randomly to treatment. Demographic and clinical factors were similar between groups, except for age. Vaginal delivery was achieved within 24 hours in 47 women (64.4%) who received hourly titrated-doses of misoprostol solution and 48 women (65.8%) who received 2-hourly static-dose misoprostol solution (P=1.00). Rates of vaginal delivery within 24 hours did not differ significantly between treatment groups for women who were nulliparous (P=1.00) or who had postterm pregnancies (P=.66), a Bishop score of ≤3 (P=.84), or oxytocin augmentation (P=.83). Cesarean deliveries were performed within 24 hours in 9 women who received hourly titrated-dose misoprostol solution and 2 women who received 2-hourly static-dose misoprostol solution (P=.056). Pyrexia and meconium-stained liquor occurred more frequently with the hourly titrated-dose regimen. The static-dose oral misoprostol solution every 2 hours has similar efficacy as hourly titrated-dose misoprostol solution but with fewer side-effects and lower complication rates.