Abstract
Objective The aim of the study is to evaluate differences in maternal and neonatal outcomes
based on updated criteria for defining active labor at 6 cm of cervical dilation and
to determine if these recommendations are cost-effective.
Study Design A decision-analytic model was built using TreeAge Pro 2020 software. We included
maternal outcomes of mode of delivery, endometritis, postpartum hemorrhage requiring
transfusion, and death. Neonatal outcomes included rates of shoulder dystocia and
permanent brachial plexus injury. Costs and quality-adjusted life years (QALYs) were
included from the maternal and infant perspectives. We used a willingness-to-pay threshold
of $100,000 per QALY and all model inputs were subjected to sensitivity analysis.
Results In a theoretical cohort of 1.4 million women, a threshold of 6 cm to define active
labor resulted in 373,668 fewer cesarean deliveries, 33,181 fewer cases of endometritis,
143 fewer postpartum hemorrhages requiring transfusions, and seven fewer maternal
deaths when compared with a threshold of 4 cm. However, there were higher rates of
adverse neonatal outcomes, including 484 more cases of shoulder dystocia and 17 more
instances of permanent brachial plexus injury. Using 6 cm as the threshold resulted
in lower costs and greater effectiveness, making it a dominant strategy. Multivariate
sensitivity analysis demonstrated the model was robust over a wide range of assumptions.
Conclusion In this model, considering 6 cm of cervical dilation as the threshold for the active
phase of labor compared with 4 cm was a cost-effective strategy to prevent primary
cesarean deliveries, lower costs, and improve maternal outcomes, despite associated
increased adverse neonatal outcomes.
Key Pointsg
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Cervical dilation of 6 cm should be considered the threshold for the active phase
of labor. This is a change from the prior definition of 4 cm.
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We built a theoretical model to compare outcomes and costs associated with the new
active phase definition of 6 cm.
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Using a 6-cm threshold is a cost-effective strategy for decreasing primary cesarean
deliveries.
Keywords
active phase - cesarean delivery - cost-effectiveness analysis - labor - labor arrest
- obstetric management
