Unsucessful labour induction in women with unfavourable cervical scores: predictors and management

Abstract

Misoprostol fails to induce labour in 5-20% of women at term. To analyse possible predictors of unsuccessful induction with 50 microg vaginal misoprostol and effectiveness and the safety of intracervical Foley catheter application in induction failures. An observational study was conducted on 1030 women with singleton, live fetuses, vertex presentation, > 34 weeks of gestation and Bishop score < 5. Induction of labour with 50 microg vaginal misoprostol repeated every 6 h was attempted. Women without regular uterine contractions and cervical changes at the end of 24 h were considered to be unsuccessful, and a transcervical Foley balloon catheter was placed and inflated with 50 mL saline. Possible predictors of induction failures were analysed via logistic regression analysis. Neonatal outcomes and vaginal delivery achieved after Foley catheter were also determined. Induction was successful in 918 cases (89.1%) and Foley catheter was placed in 112 (10.8%) women. Increasing gestational age in weeks (odds ratio [OR] 0.77, 95% confidence interval [CI] 0.68-0.88) and increasing Bishop score (OR 0.73, 95% CI 0.60-0.90) decreased the risk of failed induction. Failure rates were 16% (27/169) in post-term nulliparous women with Bishop score </= 1 and 40% (4/10) in preterm women with Bishop score </= 1. Foley catheter achieved vaginal delivery in 83% of these women without causing an increase in the adverse neonatal outcomes. When misoprostol induction fails, Foley catheter is a safe and effective method for cervical ripening. Foley catheter can be the first treatment of choice in post-term nulliparous women or preterm women with Bishop score </= 1.