671: Induction of labor with PGE1: comparison of efficacy and safety in primiparas, multiparas and grandmultiparas

The purpose of the study was to compare the efficacy and safety of induction of labor with misoprostol amongst primiparas, multiparas and grandmultiparas. We conducted a retrospective cohort study of all women who underwent induction of labor with prostaglandin E1. Inclusion criteria included term singleton pregnancies. Exclusion criteria included multiple gestation, history of Cesarean delivery, and fetuses with intrauterine growth restrictions or known anomalies. All women received 50 micrograms misoprostol orally and this dose was repeated every four hours if active labor did not develop, up to a maximal dose of 300 micrograms. We divided the women into three groups: primiparas, multiparas (defined as parity of 1-4), and grandmultiparas (defined as para 5 and above). Primary outcome was mode of delivery and secondary outcome was neonatal 5 minute Apgar and umbilical cord (UA) pH. We defined efficiency as the duration from administration of the first cytotec dose until delivery. We also collected data on maternal and neonatal complications. Between January-December 2017, 1713 women underwent induction of labor: 523 were primiparas, 656 were multiparas and 534 were grandmultiparas. Four hundred and seventy-nine (91.6%) primiparas delivered vaginally as did 640 (97.6%) multiparas and 521(97.6%) grandmultiparas. Induction to delivery interval was significantly longer in primiparas (mean: 29.7 hours; 95% CI: 27.8-31.7 hours), and there was no significant difference between multiparas (mean: 18.6 hours; 95% CI: 17.3-20.0 hours) and grandmultiparas (mean: 18.6 hours; 95% CI: 17.0 -20.1 hours). There were no cases of uterine rupture, and the rates of postpartum hemorrhage and endometritis were similar among the three groups The rate of 5 minute Apgar score below 7 and UA pH<7.1 were not significantly different between the groups. Using misoprostol for labor induction is efficient and safe in primiparas, multiparas, and grandmultiparas.