Comparison of perinatal outcomes using oral misoprostol, vaginal misoprostol, and intracervical dinoprostone for induction of labor.

Objective: To compare the effectiveness and safety of the methods of pharmacological induction of labor. To identify the advantages and disadvantages of oral and vaginal administration of misoprostol and intracervical administration of dinoprostone.

Materials and methods: Analysis of a group of women who gave birth at the Faculty Hospital Brno from 1st August 2019 to 31st January 2020, and one of the following labor induction schemes was used: group A: misoprostol 25 µg orally every 2 hours, group B: misoprostol 50 µg vaginally every 6 hours, group C: intracervical dinoprostone 1 mg every 2 hours. Inclusion criteria were: singleton pregnancy, completed 36th gestational week, live fetus, cephalic presentation, and cervix score ≥ 6. Exclusion criteria were uterine scars and fetal growth restriction. Time factors of induction, occurrence of acute hypoxia during labor, mode of delivery, use of tocolysis during labor, necessity of oxytocin infusion, use of epidural analgesia, blood loss, uterine rupture, umbilical artery pH, and Apgar score at the 5th min were evaluated.

Results: A total of 378 women were included (133 vs. 145 vs. 100). A statistically significantly higher success rate of vaginal delivery was demonstrated in group A compared to groups B and C (88 vs. 77.9 vs. 76%; P = 0.035). The longest time from the administration of the first dose of the preparation to delivery of the fetus was in group A (medians in minutes 700 vs. 565 vs. 375; P < 0.0001). There was no difference between the groups in the I. and II. labor stage duration. Cesarean delivery rate due to acute hypoxia was the lowest in group A (2.3 vs. 10.3 vs. 9%; P = 0.023). Uterine rupture was not recorded; there were no differences in neonatal outcome parameters.

Conclusion: The highest success rate of vaginal delivery was achieved with the use of low-dose oral misoprostol. The disadvantage of this method is a significant increase in the time from the start of induction to the delivery of the fetus. There was no difference in the occurrence of severe perinatal complications between the induction methods.