Is high-dose misoprostol able to lower the incidence of cesarean section? A randomized controlled trial

Abstract

Objective: To determine whether high-dose (100 microg) misoprostol was able to increase the rate of successful labor induction and lower the incidence of Cesarean section without adverse fetal effects.

Methods: A total of 360 women were randomized to receive either oxytocin (n = 192) by intravenous infusion, or misoprostol (n = 168) 100 microg intravaginally every 4 h. The Cesarean section rate was the primary end-point. Incidences of uterine and fetal heart rate abnormalities during labor and adverse neonatal outcomes were assessed as secondary end-points.

Results: Compared with those women receiving oxytocin, patients given misoprostol had a significantly shortened labor (10.7+/-6.0 vs. 15.4+/-10.4 h, p < 0.001). The Cesarean section rate did not differ between patients receiving misoprostol or oxytocin (36 (21.4%) vs. 38 (19.8%), p = 0.79) despite a sample size adequate to detect a 13 percentage point difference in this outcome. Patients receiving misoprostol had a higher incidence of the hyperstimulation syndrome (27 (16.1%) vs. 9 (4.7%), p < 0.001), and of fetal intolerance of labor as an indication for Cesarean delivery (23 (63.9%) vs. 15 (39.5%), p = 0.06), and had a greater number of umbilical artery cord blood pH findings of< 7.20 (20 (43.5%) vs. 6 (17.1%), p = 0.02). These worrisome trends on interim analysis resulted in our prematurely terminating the study.

Conclusion: High-dose intravaginal misoprostol did not reduce the Cesarean section rate and was associated with a greater hazard of fetal intolerance of labor.