Length of first stage of labor: Is it predictive of perinatal outcomes?

Abstract

YVONNE W. CHENG (F), TINA O. TAN, ALLISON S. BRYANT, LINDA M. HOPKINS, NAOMI E. STOTLAND, AARON B. CAUGHEY, University of California, San Francisco, Obstetrics, Gynecology and Reproductive Sciences, San Francisco, California OBJECTIVE: To examine how length of 1st stage of labor is associated with maternal and neonatal outcomes. STUDY DESIGN: This is a retrospective cohort study of 17,264 nulliparous women with term, singleton pregnancies, excluding cesarean delivery without labor. Length of 1st stage of labor was stratified by multiples of the median (MoM). Maternal and neonatal outcomes were compared between each successive subgroup by chi-square test for trend for categorical outcomes. In order to determine the change in risk from increasing by one median, the categorical variable was included in a multivariate logistic regression model along with potential confounding factors. RESULTS: The median length of 1st stage for the study population was 9.75 hours. Rates of cesarean delivery and maternal complications increased with lengthening 1st stage of labor. Duration of 1st stage was associated with higher risks for 5-minute apgar !7 and meconium stained amniotic fluid (see Table). For example, the risk of chorioamnionitis was 5 times higher in patients with a first stage of labor 2 MoM above the median as compared to those below the median (p!0.001). CONCLUSION: Even when controlling for potential confounders, there was a statistically and clinically significant increase in perinatal morbidity when increasing from one median length of labor category to the next, throughout labor. These differences can be used to adjust clinical suspicion for complications of labor and delivery throughout the labor course.