(537) Misoprostol with Balloon Compared to Oxytocin with Balloon in High-Risk Pregnancy: A Randomized Controlled Trial

This was a single-center open-labeled randomized controlled trial (RCT). Individuals at least 18 years old, at > 22 weeks’ gestational age with a live singleton cephalic fetus, Bishop score < 6, and intact membranes were offered enrollment. Participants required at least one of the following high-risk conditions: hypertensive disease of pregnancy, fetal growth restriction (FGR; defined as the estimated fetal weight or abdominal circumference < 10^th percentile), oligohydramnios (defined as deepest vertical pocket < 2cm), suspected placental abruption requiring delivery, uncontrolled pre-gestational diabetes, or abnormal fetal testing by biophysical profile or non-stress test requiring delivery. The primary outcome was the rate of cesarean delivery. The sample size was based on an internal retrospective chart review assessing the cesarean rate of high-risk pregnancies induced at our institution. We estimated a priori that 150 subjects would afford an 80% power to detect a 50% difference in cesarean delivery (baseline rate 45%, 2-tailed, alpha=0.05). An intent-to-treat analysis was performed. This RCT was approved by the IRB and was registered on ClinicalTrials.gov (NCT04492072).

Results:

During the 22 months of the trial, 305 were eligible, of which 150 (49%) were randomized. 77 (51%) received MB, and 73 (49%) received OB. The maternal demographics and high-risk factors were comparable between the groups. There was no significant difference in the rate of overall cesarean delivery between study groups, (31.1% vs 21.9%; RR 0.70, 95% CI 0.41-1.21), nor for those performed for a specific indication (Table 1). There were also no differences in secondary maternal or neonatal outcomes (Table 2).

Conclusion:

There is no significant difference in cesarean delivery rates in high-risk pregnancies induced with misoprostol and balloon compared to oxytocin and balloon.