Factors associated with delayed onset of active labor following administration of vaginal Misoprostol among women at Mbarara Regional referral hospital, Uganda: A prospective cohort study

Abstract

Background: Vaginal misoprostol has been recommended by the World Health Organization as one of the effective methods for induction of labor. Globally 9.6% of all deliveries follow induction of labor. Although the goal of labor induction is to initiate active labor with subsequent vaginal delivery, some mothers undergoing labor induction delay to get into active labor and some fail completely. The factors associated with delayed onset of active labor following labor induction with vaginal misoprostol have not been sufficiently explored in resource limited settings. Methods: We conducted a prospective cohort study over a period of 6 months on the antenatal ward and labor suit of Mbarara Regional Referral Hospital, southwestern Uganda. We enrolled mothers of gestational age at least 28 weeks, with indication for labor induction. They received 50 micrograms of vaginal misoprostol every 6 hours with a maximum of 4 doses and were followed up until onset of active labor. Onset of active labor was considered delayed if it occurred at more than 12 hours after administration of the first dose of vaginal misoprostol. Bivariate and multivariate analysis was done to determine the factors associated with delayed onset of active labor. Results: Eighty-eight mothers underwent induction of labor, 22.7% had delayed onset of active labor. After adjusting for potential confounders, low/no parity (Relative Risk or RR 2.67, p-value=0.01), low gestational age (RR 3.1, p-value=0.006) and higher BMI (RR 0.36, p-value=0.005), were associated with delayed onset of active labor following vaginal misoprostol administration. Conclusion: Null parity, gestational age less than 37weeks are associated with delayed onset of active labor following labor induction with vaginal misoprostol while BMI of 26 and above is protective from delayed onset of labor.