(1139) Short inter-delivery intervals do not affect TOLAC success and safety

We performed a retrospective cohort study at a single tertiary center between 2008 and 2021. We compared maternal and neonatal outcomes in pregnant women who had one prior cesarean delivery (CD) and attempted TOLAC. Patients were stratified based on the IDI starting from an IDI of 10 months up until 24 months. Women with an IDI < 18 were advised to consider a repeated cesarean delivery (CD) based on ACOG guidelines stating the increased risk of uterine rupture under these timing circumstances. Exclusion criteria included multiple gestations, known fetal anomalies and preterm birth. The primary outcome was the rate of repeated CD. The secondary outcomes included uterine rupture rate, and maternal and neonatal adverse outcomes. We performed multivariable analysis of maternal and neonatal adverse outcomes using the group of patients with an IDI >24 months as our point of reference.

Results:

A total of 3254 had an IDI < 24 months and 3443 had an IDI >24 months. As shown in Table 1, there were no differences in basic demographic and obstetric parameters including risk factors previously associated with TOLAC success and safety. After stratification based on IDIs ranging from < 12 months to >24 months and multivariable analysis that took into account age, body mass index, parity, previous vaginal deliveries, timing of previous CD, gestational age at delivery, induction of labor, oxytocin use, birthweight, and 2^nd stage duration, there were no significant differences found in repeated CD rates (p=0.46), uterine rupture rates (p=0.38), rates of a composite of maternal morbidity (p=0.25), and rates of a composite of neonatal morbidity (p=0.29).

Conclusion: Our data suggests that there was no association between short birth intervals and adverse obstetric outcomes including uterine rupture.