117 Clinically defined active phase arrest of labor in nulliparous women

Abstract

We sought to examine maternal and neonatal outcomes in women who achieved the active phase of labor and evaluated the duration of time to progress at least 1 cm. This was a retrospective cohort study of nulliparous women with term singleton in a cephalic presentation who presented with spontaneous labor and achieved active labor. Women were categorized based on the time interval it took to make at least 1 cm of cervical change (less than 4 hours, 4-5.9 hours, 6 hours or greater). Analyses were performed at cervical dilation of 6, 7, 8, and 9 cm. Outcomes that were examined included cesarean delivery, chorioamnionitis, and a composite of neonatal outcomes including intensive care unit admission, seizure, ventilator use, birth injury, or asphyxia. Adjusted odds ratios (aORs) with 95% confidence intervals (95%CIs) were calculated, controlling for predefined covariates. Of 31,505 nulliparous women, there were 13,142 (42%), 10,855 (34%), 11,761 (37%), and 17,049 (54%) who had documented cervical dilation of 6, 7, 8, and 9 cm, respectively (Figure). Rates of women who took 6 hours or greater to make at least 1 cm cervical change decreased as cervical dilation progressed. Overall, results were similar regardless of cervical dilation. For example, if we look at the time interval for women to make cervical change starting at 8 cm; women who took less than 4 hours to make cervical change from 8 cm compared to those who took 4-5.9 hours had lower rates of cesarean delivery (aOR 0.40; 95%CI 0.28-0.55), chorioamnionitis (aOR 0.42; 95%CI 0.29-0.60), and the neonatal composite outcome (aOR 0.51; 95%CI 0.36-0.72). However, women who took 6 hours or greater had similar rates of cesarean delivery (aOR 1.14; 95%CI 0.78-1.69), chorioamnionitis (aOR 1.30; 95%CI 0.83-2.03), and the neonatal composite outcome (aOR 1.18; 95%CI 0.70-2.00). While women who took less than 4 hours to make cervical change had lower rates of maternal and neonatal outcomes compared to those who took 4-5.9 hours, those who took 6 hours or greater did not have increased rates of maternal and neonatal outcomes.View Large Image Figure ViewerDownload Hi-res image Download (PPT)