(361) Premature rupture of membranes and risk of uterine rupture in trial of labor after cesarean

To evaluate whether premature rupture of membranes (PROM) is independently associated with an increased risk of uterine rupture in women undergoing a trial of labor after cesarean delivery (TOLAC).

Study Design:

We conducted a retrospective cohort study including all singleton term pregnancies with one prior cesarean delivery attempting TOLAC at a tertiary care center between 2011 and 2023. PROM and uterine rupture cases were identified by ICD-9 codes and validated by chart review. Multivariable logistic regression adjusted for parity, gestational age, birthweight, prior vaginal birth after cesarean (VBAC), and labor induction. Subgroup analyses compared rupture rates by PROM status within spontaneous and induced labor groups.

Results:

Of 9,551 TOLAC candidates, 1,040 (10.9%) had PROM. Uterine rupture occurred in 37 cases (0.38%). The rupture rate was higher with PROM versus no PROM (1.0% vs. 0.3%; unadjusted OR 3.05, 95% CI 1.47–6.32; p=0.002). PROM remained independently associated with rupture (adjusted OR 2.65, 95% CI 1.25–5.63; p=0.011). Labor induction increased rupture risk (adjusted OR 2.78, 95% CI 1.41–5.46; p=0.003), while higher parity was protective (adjusted OR 0.82, 95% CI 0.69–0.98; p=0.026). In induced labors, rupture was more frequent with PROM (2.4% vs. 0.8%; p=0.047). In spontaneous labors, PROM showed a nonsignificant trend toward increased rupture risk (0.6% vs. 0.2%; p=0.073).

Conclusion:

PROM independently increases uterine rupture risk in women undergoing TOLAC, with the greatest risk observed when induction is required. PROM should be recognized in risk stratification and counseling for TOLAC candidates.