Comparison of the Efficacy and Safety of Sublingual Versus Oral Misoprostol for the Induction of Labor: A Randomized Open-Label Study

IntroductionMisoprostol (prostaglandin E1 analog) is being used for the induction of labor by vaginal, oral, and sublingual routes. Oral misoprostol is the preferred route for induction of labor, but the use of sublingual misoprostol appears promising due to a faster onset of action. This study was done to compare the efficacy and safety of oral and sublingual misoprostol for induction of labor in term pregnancy.Materials and methodsOne hundred and sixty patients were randomly allocated to one of the two groups to receive 50 micrograms of oral and sublingual misoprostol four hourly for a maximum of six doses. Primigravida at 37-42 weeks of gestation with singleton pregnancy, cephalic presentation, Bishop score (<5), and reassuring fetal heart rate were included in the study. Misoprostol dose was withheld if the active phase of labor was reached or if the cervix was favorable for amniotomy (Bishop score greater than or equal to eight). The change in the Bishop score with misoprostol was studied along with adverse effects and neonatal outcomes.ResultsThe mean number of 50 mcg misoprostol doses required was significantly less in the sublingual group (2.94 +/- 0.97 versus 2.13 +/- 0.92; p<0.0001). The rate of change of the mean Bishop score was faster in the sublingual group. After four hours of the first dose, the mean Bishop score changed to 3.52 +/- 2.14 versus 4.68 +/- 2.34 (p=0.001), and, similarly, after eight hours, it was 10.48 +/- 2.59 versus 11.39 +/- 2.06, and this difference was statistically significant (p=0.015). The mean induction delivery interval was significantly lower in the sublingual group. The need for labor augmentation, mode of delivery, and adverse effects were similar in both groups. The incidence of meconium-stained liquor and NICU admission was also similar in both groups.ConclusionSublingmisoprostolstol has a short induction delivery interval and comparable side effects when compared to omisoprostolstol. Sublingmisoprostolstol is recommended for induction of labor at term.