91: Pushing the bounds of second stage: when should we abandon the ambition of SVD?

Abstract

To develop a prediction model for spontaneous vaginal delivery per hour during the second stage of labor in nulliparous women with epidural anesthesia. This was a secondary analysis of the Consortium for Safe Labor database. Primary outcome was delivery type per hour of second stage: spontaneous vs operative (operative vaginal and cesarean delivery). Inclusion criteria: term, nulliparas, singleton gestations, vertex presentation, epidural anesthesia who reached 10 centimeters cervical dilation. Exclusion criteria: intrauterine fetal demise, planned cesarean delivery and major congenital anomalies. Univariate comparisons were made to identify variables that were independently associated with spontaneous vaginal delivery. An optimal decision tree was used to create a prediction model. A test set was withheld from the dataset to perform validation. A risk calculator tool was developed for prediction of spontaneous vaginal birth as well as adverse perinatal outcomes per hour. Adverse maternal outcomes were a composite of postpartum hemorrhage, transfusion, endometritis, 3rd/4th degree laceration. Adverse neonatal outcomes were a composite of neonatal intensive care unit admission, hypoxic ischemic encephalopathy, respiratory distress, seizures, apnea, asphyxia and shoulder dystocia. The study population included 228438 deliveries, 26796 patients met inclusion and exclusion criteria. After removing cases with incomplete data the study population consisted of 22299 women, of which 16593 women had a spontaneous vaginal delivery (74.4%). Number deliveries at a given hospital/year, fetal position, cervical dilation on admission, chorioamnionitis, augmentation of labor, maternal age and length of second stage were associated with the odds of spontaneous vaginal delivery. Using the predictors identified, a risk predictor calculator was created. An ROC curve was developed to assess the calculator; AUC was 0.74 for the validation set: This calculator is available at: https://www.interpretable.ai/CSL_study/questionnaire.html Spontaneous vaginal delivery for women with term, cephalic, singleton gestations with epidural anesthesia was associated with several variables. This calculator tool will help facilitate provider decision making and patient counseling about the value of continuing the second stage of labor based on changing rates of success and risks of maternal and neonatal morbidity with time.