The effect of prior vaginal births on labor outcomes among women with previous cesarean delivery: 974

Abstract

974 The effect of prior vaginal births on labor outcomes among women with previous cesarean delivery Maya Ram, Liran Hiersch, Eran Ashwal, Daniel Nassie, Anat Lavie, Yariv Yogev, Amir Aviram Lis Maternity and Women’s Hospital, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel, Tel-Aviv, Tel-Aviv, Israel, The Helen Schneider Hospital for Women, Rabin Medical Center, Petah-Tikva, Israel, Petah-Tikva, Tel-Aviv, Israel OBJECTIVE: It is well established that trial of labor after cesarean delivery (TOLAC) is associated with higher success rate in the presence of at least one prior vaginal delivery (VD). Yet, the magnitude of impact of each additional prior VD on the success rate is yet to be answered. Therefore, we aimed to characterize the additive effect of each additional previous VD among women attempting TOLAC. STUDY DESIGN: A retrospective cohort study of all women attempting TOLAC with singleton pregnancy at term who delivered at a single, tertiary medical center, between 2007-2014. The primary outcome was defined as mode of delivery. Secondary outcomes included uterine rupture, composite maternal morbidity (defined as 1 of the following: uterine rupture, postpartum hemorrhage, or postpartum transfusion) and composite neonatal morbidity (defined as 1 of the following: mechanical ventilation, respiratory distress syndrome, arterial cord pH<7.05, 5-minutes Apgar score<7, birth asphyxia, hypoxic-ischemic encephalopathy, or neonatal death). Women without any prior VD were compared to women with one prior VD, which were compared to women with two previous VDs, which were compared to women with three or more previous VDs (Figure). RESULTS: During the study period, 2,772 women were eligible for the analysis: 1,219 (44.0%) women had no prior VD, 845 (30.5%) had one prior VD, 398 (14.4%) had two prior VDs and 310 had three or more prior VDs (11.1%) (Fig 1). Compared to no prior VD, the presence of any number of VDs was associated with higher rate of achieving vaginal delivery (p<0.001), with no significant differences between the groups who have had at least one previous VD. No differences were found with regards to the rate of uterine rupture (p1⁄40.4). A history of at least one previous VD increased the chance of achieving VD and decreased the risk of maternal and neonatal adverse outcomes. No such effect was found in the comparison of two previous VDs to one prior VD, or in the comparison of three or more previous VDs to two previous VDs (Table). CONCLUSION: One prior VD improves the chances of having a VD in the index pregnancy, and additional prior VDs do not seem to increase this success rate significantly.