Maternal and perinatal outcomes of failed prostaglandin induction of labour: A retrospective cohort study

BACKGROUND: Induction of labor is performed in up to 25% of pregnant women. When the cervix is unfavorable, cervical ripening may be safely and effectively performed using slow-release vaginal inserts of prostaglandin E2. However, the risk factors, management, and outcome of patients who fail to respond remain unclear. OBJECTIVE: To evaluate the outcomes of women who fail to respond to cervical ripening with prostaglandins. METHODS: A retrospective cohort analysis (2013–2019) was conducted. Women with a singleton gestation who underwent induction of labor due to post-date pregnancy using a slow-release prostaglandin E2 vaginal insert for cervical ripening were included. Data on clinical and outcome factors were derived from the medical files, and findings were compared between patients who achieved ripening within 24 h of treatment onset and those who did not. The primary outcome measure was the vaginal delivery rate following the ripening process. Secondary outcome measures were adverse composite maternal and neonatal outcomes. A model combining maternal characteristics and response rates to ripening was constructed. RESULTS: The final cohort included 1285 women: 1202 responded to cervical ripening (93.54%) and 83 (6.46%) did not. Compared to non-responders, responders had higher rates of vaginal delivery (96.51% vs. 66.27%, P < 0.001); lower rates of adverse maternal composite outcome (12.81% vs. 24.10%, P = 0.031) and adverse neonatal composite respiratory outcome (1.33% vs. 6.02%, P = 0.009). Responders were younger than non-responders (mean 30.03 years vs 31.73 years, P = 0.005) and had a lower nulliparity rate (50.99% vs 76.92%, P < 0.001). On multivariate analysis, failure to achieve cervical ripening was an independent risk factor for intrapartum cesarean delivery due to prolonged labor (aOR 11.90, 95% CI 6.13–23.25). CONCLUSION: Women who achieve cervical ripening with prostaglandin E2 vaginal inserts are younger and more often multiparous than women who fail to respond. Good response to the cervical ripening process is associated with lower rates of intrapartum cesarean delivery and of adverse outcomes.