Risk of uterine rupture in multiparous women after induction of labor with prostaglandin: A national population-based cohort study

Objective To assess whether, after induction of labor with prostaglandin, multiparous (>= 2 para) women have an increased risk of uterine rupture compared with nulliparous or uniparous women.Methods This was a retrospective population-based cohort study including women who underwent induction with prostaglandin in all maternity wards in Sweden between May 1996 and December 2019 (n = 56 784). The study cohort was obtained by using data from the Swedish Medical Birth Register, which contains information from maternity and delivery records. The main outcome measure was uterine rupture.Results Overall, multiparous women induced with prostaglandin had an increased risk of uterine rupture compared with nulliparous women (adjusted odds ratio [OR], 3.33 [95% confidence interval (CI), 1.38-8.04]; P < 0.007). Multiparous women with no previous cesarean section (CS) induced with prostaglandin had more than three times higher risk of uterine rupture (crude OR, 3.55 [95% Cl, 1.48-8.53]; P = 0.005) compared with nulliparous women and four times higher risk compared with uniparous women (OR, 4.10 [95% CI, 1.12-15.00]; P < 0.033). Multiparous women with previous CS had a decreased risk of uterine rupture compared with uniparous women with one previous CS (crude OR, 0.41 [95% Cl, 0.21-0.78]; P = 0.007).Conclusion Our study implies that multiparity in women with no previous CS is a risk factor for uterine rupture when induced with prostaglandin. This should be taken into consideration when deciding on the appropriate method of induction.