Mechanical vs. pharmacological cervical ripening in intrauterine growth restriction (FGR): A propensity score-weighted cohort study

Objective To compare obstetric and neonatal outcomes following mechanical versus pharmacological cervical ripening in pregnancies complicated by fetal growth restriction (FGR) and an unfavourable cervix. Study design We conducted a single-centre retrospective cohort study including all women with FGR who underwent labour induction between January 2017 and December 2022. Women were classified according to the initial ripening method: Cook® balloon (mechanical) or prostaglandins (vaginal dinoprostone or oral misoprostol). The primary outcome was vaginal delivery. The secondary outcome was a composite neonatal morbidity endpoint including 5-minute Apgar score < 7, umbilical arterial pH < 7.15, or neonatal intensive care unit admission. Propensity score weighting was applied for the primary outcome. Neonatal outcomes were analysed using adjusted logistic regression models accounting for gestational age and mode of delivery. Results A total of 133 women were included (66 balloon; 67 prostaglandins). After propensity score weighting, no difference was observed in vaginal delivery rates between groups (weighted OR 1.01, 95% CI 0.38–2.72). For neonatal outcomes, no significant association was observed in unadjusted analyses. In adjusted models, a non-significant trend toward increased neonatal morbidity was observed in the prostaglandin group (aOR 2.57, 95% CI 0.96–7.54). In exploratory subgroup analysis, oral misoprostol was associated with a higher risk of adverse neonatal outcome compared with the balloon group (aOR 9.47, 95% CI 2.74–38.2), whereas vaginal prostaglandins were not. Conclusion In this exploratory cohort of pregnancies complicated by FGR, mechanical and pharmacological cervical ripening resulted in similar vaginal delivery rates. A signal toward increased neonatal morbidity was observed with prostaglandins, particularly oral misoprostol, although estimates were imprecise and based on small numbers. These findings should be considered hypothesis-generating and require confirmation in adequately powered prospective studies.