Impact of the interpregnancy interval after cesarean delivery on subsequent perinatal risks: a retrospective study

To assess the impact of the interpregnancy interval (IPI) after cesarean delivery on the risks of adverse perinatal events during subsequent pregnancies.

We retrospectively examined perinatal outcomes of subsequent pregnancies of women whose most recent birth experience involved cesarean delivery at our hospital between January 2014 and December 2019. IPI was defined as the time between live birth and subsequent conception. Three IPI groups: < 18 months, 18-60 months, and > 60 months, were assessed. The risks of preterm birth, preeclampsia, placenta previa, placental abruption, fetal growth restriction, and successful vaginal birth were compared among the three IPI groups using uni- and multivariate analyses.

We registered 592 births after cesarean delivery: 178, 288, and 126 in the IPI < 18 months, 18-60 months, and > 60 months groups, respectively. The groups did not differ significantly regarding perinatal outcomes. The multivariate analysis revealed no significant differences in the risks of adverse perinatal outcomes among all groups. The odds ratios (ORs) for preterm birth at < 37 weeks of gestation were 1.24 and 1.64 for those in the < 18 months and > 60 months groups, respectively (P = 0.362 and P = 0.055, respectively). The groups did not differ significantly regarding vaginal birth success rate (ORs 1.72 for the < 18 months group, 0.49 for the > 60 months group; P = 0.486 and P = 0.446, respectively).

After cesarean delivery, IPIs shorter than 18 months and longer than 60 months do not significantly impact the risks of adverse perinatal outcomes or successful vaginal birth compared with IPIs of 18-60 months.