Is Use of Misoprostol Associated With Failed Induction in Pregnancies With Suspected Placental Insufficiency? [12O

Abstract

INTRODUCTION: Although misoprostol (MP) has demonstrated efficacy for cervical ripening, a concern with use of MP is uterine tachysystole, leading to fetal intolerance of labor and cesarean delivery (CD). We sought to determine whether indicators of placental insufficiency were associated with higher rates of failed induction and CD in pregnancies when MP was used for cervical ripening. METHODS: Population based retrospective cohort study of patients who underwent MP induction between May 2008-2013. Maternal and labor characteristics were compared between patients with FGR (<10th% estimated fetal weight on ultrasound), oligohydramnios, preeclampsia, and infants born SGA (birth weight less than 10th%). Primary outcome was rate of CD. Secondary outcomes included CD for nonreassuring fetal status (NRFS). Multivariable logistic regression estimated association between indicators of placental insufficiency on the outcome of CD. RESULTS: Of 1,617 inductions during the 6 year period, 580 patients were induced using MP. FGR was suspected in 106 (18.2%). FGR was not associated with higher CD rate in MP inductions [22% versus 29%, p=0.11 (aOR 0.89, 95% CI 0.68-1.16)]. Similarly neither SGA nor oligohydramnios were associated with an increased CD rate, however preeclampsia did demonstrate a trend toward increased CD, aOR 1.21 (95% CI 0.97-1.51). The rate of CD for NRFS was similar between those with FGR and those without FGR (16% vs 15%, p=0.7). CONCLUSION: Despite a biologically plausible concern that MP induction in the setting of FGR and other indicators of placental insufficiency may increase risk for CD and CD for NRFS, our data does not support this.