Cervical ripening with multiple medical or combined induction methods: Risks of subsequent preterm birth in nulliparous women

Objective: To determine the impact of combined medical and medical/mechanical methods for cervical ripening on the risk of preterm birth in subsequent pregnancy, in nulliparous women.

Methods: A retrospective cohort study of nulliparous women with term singleton gestations induced by single or combined methods at one center who had their subsequent second birth in the same center. Study groups were compared with a control group of nulliparous women not induced. The primary outcome was risk of preterm labor in the second consecutive birth. Secondary outcomes included neonatal and maternal complications.

Results: Cohort included 1277 nulliparous women who underwent cervical ripening by single or combined methods. The study group consisted of 942 women induced by one dose of prostaglandin E₂ , 248 women induced by combined methods, and 87 women induced by a mechanical method. The control group consisted of 3903 women. Demographic data of the groups were comparable. Rates of spontaneous preterm birth and early spontaneous preterm birth in the subsequent births did not differ between the groups.

Conclusion: Cervical ripening with combined methods or multiple medical methods did not increase the rate of subsequent spontaneous preterm births in nulliparous women or change the neonatal and maternal complications rate.