Evaluation of the efficacy of labor induction with vaginal misoprostol in a low-risk pregnant women population.

Objective: The aim of this study was to evaluate the success rate and predictors of labor induction using vaginal misoprostol in a low-risk pregnant women population.

Methods: A prospective cohort study was carried out with 196 pregnant women. Groups 2 and 4 of the Robson Classification admitted for induction of labor with vaginal misoprostol (25 μg tablets every 6 h, up to 4 tablets, for a maximum of 24 h). The success of labor induction was considered the achievement of vaginal delivery. Binary logistic regression was used to determine the best predictors of successful induction of labor with vaginal misoprostol.

Results: Of all the pregnant women analyzed, 140 (71.4%) were successful and 56 (28.6%) were unsuccessful. Pregnant women who achieved successful induction had a higher number of pregnancies (1.69 vs. 1.36, p=0.023), a higher number of deliveries (0.57 vs. 0.19, p<0.001), a higher Bishop score (2.0 vs. 1.38, p=0.002), and lower misoprostol 25 μg tablets (2.18 vs. 2.57, p=0.031). No previous deliveries [x2(1)=3.14, odds ratio (OR): 0.24, 95% confidence interval (CI): 0.10-0.57, R2 Nagelkerke: 0.91, p=0.001] and the presence of one previous delivery [x2(1)=6.0, OR: 3.40, 95% CI: 1.13-10.16, R2 Nagelkerke: 0.043, p=0.029] were significant predictors of successful induction of labor with vaginal misoprostol.

Conclusion: A high rate of labor induction success using vaginal misoprostol in a low-risk population was observed, mainly in multiparous and with gestational age>41 weeks. No previous delivery decreased the success of labor induction, while one previous delivery increased the success of labor induction.