967: Reconsidering criteria for active phase labor management: a cost-effectiveness analysis

Abstract

Recommendations from ACOG for the safe prevention of primary cesarean delivery propose that cervical dilation of 6cm should be considered the threshold for the active phase of labor. This is a change from considering 4cm. This study seeks to evaluate differences in maternal and neonatal outcomes based on updated criteria for defining active labor and to determine if these recommendations are cost effective. A cost-effectiveness analysis model was built using TreeAge Pro 2019 software with model inputs derived from the literature. We used a theoretical cohort of 1.4 million women, approximately the number of nulliparous U.S. women reaching 4cm in spontaneous labor. We compared outcomes and costs associated with defining active phase at 6cm versus 4cm and considering arrest after 2 hours versus 4 hours of no cervical progression. It was assumed that women with active phase arrest were delivered via cesarean. In addition to cost and maternal quality-adjusted life years (QALY), outcomes included mode of delivery, endometritis, postpartum hemorrhage requiring transfusion, and maternal deaths. Neonatal outcomes included rates of shoulder dystocia and permanent brachial plexus injury. A cost-effectiveness threshold was set at $100,000/QALY. In a cohort of 1.4 million women, considering the threshold of active phase of labor at 6cm led to 373,668 fewer cesareans assuming only 2 hours of waiting was used, and 154,622 fewer cesareans even with waiting 4 hours to diagnose active phase arrest. The 6cm threshold was the dominant strategy as it resulted in lower costs and greater effectiveness (Table 1). This strategy is dominant whether you wait 4 hours or 2 hours before diagnosing active phase arrest. Defining active phase as starting at 6cm resulted in fewer cesareans and improved maternal outcomes. Rates of shoulder dystocia and permanent brachial plexus injury, however, were higher with longer labors. Considering 6cm of cervical dilation as the threshold for the active phase of labor is a dominant strategy for decreasing primary cesarean rates and improving overall outcomes.