580: Non labor cesarean delivery - Is this a risk factor for uterine rupture during TOLAC?

Abstract

The indication for primary cesarean delivery (CD) influences the chances for successful vaginal birth after cesarean (VBAC). Non-labor CD is associated with less developed lower uterine segment. We aimed to determine whether indication and labor status at primary CD alters the risk for uterine rupture. A retrospective case-control study of women having trial of labor after cesarean (TOLAC) in a single, tertiary, university affiliated medical center between August 1st 2007 and June 30th 2016. Deliveries complicated by uterine rupture were matched to successful vaginal deliveries by gravity, parity, gestational age, induction of labor and birth weight at index delivery in a 1:3 ratio. All cases medical charts were manually reviewed by study personnel to obtain maternal and primary CD data including previous vaginal birth after cesarean (VBAC), indication for CD, the labor stage in which it happened and CD complications. In-labor CD was defined if ≥3 cm dilatation and regular contractions. Indications for primary CD and CD characteristics were compared between study and control groups. Overall, during study period there were 75,682 deliveries, of them, 3,937 were TOLAC. Study group included 53 (1.34%) cases of uterine rupture at TOLAC that were matched to 159 women with successful VBAC (control group). Demographic and obstetrical data did not differ between groups. Indications to CD were similar in study and control groups (P>0.05, Figure). In-labor CD did not alter risk for uterine rupture at TOLAC. Women in study group had significantly lower rates of previous VBAC (15.1% vs. 28.9%, p=0.047) and higher rates of postpartum hemorrhage following the primary CD (3.7% vs. 1.25%, p=0.042, Table). Utilizing the multivariate logistic regression analysis, previous VBAC and postpartum hemorrhage at primary CD were no longer associated with uterine rupture. In our cohort, Indication, labor status and complications in primary CD did not alter the risk for uterine rupture.View Large Image Figure ViewerDownload Hi-res image Download (PPT)