Neonatal mortality risk for repeat cesarean compared to vaginal birth after cesarean (VBAC) deliveries in the United States, 1998-2002 birth cohorts

Abstract

To examine trends in repeat cesarean delivery, the characteristics of women who have repeat cesareans, and the risk of neonatal mortality for repeat cesarean birth compared to vaginal birth after cesarean (VBAC). Trends and characteristics of repeat cesareans were examined for: the period 1998-2002 for [1] all births, [2] low-risk births (singleton, term, vertex births) and [3] "no indicated risk" (NIR) births (singleton, term, vertex presentation births with no reported medical risks or complications). For low-risk and NIR births, neonatal mortality rates for repeat cesareans and VBACs were compared. Multivariate logistic regression was used to examine the risk of neonatal mortality for repeat cesareans and VBACs, after controlling for demographic and health factors. In 2002 the repeat cesarean rate was 87.4%, and varied little by maternal risk status or by demographic and health characteristics. From 1998-2002 rates increased by 20% for low risk and by 21% for NIR births, respectively. For low-risk women for the 1998-2002 birth cohorts, the adjusted odds ratio for neonatal mortality associated with repeat cesarean delivery (compared with VBAC) was 1.36 (95% C.I. 1.20-1.55). For NIR women, the adjusted odds ratio was 1.24 (0.99-1.55). The experience of a prior cesarean has apparently become a major indication for a repeat cesarean. Regardless of maternal risk status, almost 90% of women with a prior cesarean have a subsequent (i.e., repeat) cesarean delivery. This is the case even if there was no other reported medical indication. Our findings do not support the widely-held belief that neonatal mortality risk is significantly lower for repeat cesarean compared to VBAC delivery.