962: Admission factors vs. intrapartum factors: What matters more in predicting a second stage cesarean delivery?

Abstract

To identify risk factors associated with second stage cesarean delivery (CD) in laboring patients and compare the predictive ability according to clinical factors available at admission and intrapartum clinical risk factors. This is a retrospective cohort study performed in a single center institution from 2004-2014 of term non-anomalous singleton pregnancies admitted for delivery. The primary outcome was second stage CD, defined as CD after complete dilation. The relative risk of second stage CD was calculated for each admission risk factor (demographics, antenatal history, and medical history) and each intrapartum risk factor (pharmacologic and mechanical agents, duration of labor, and need for induction). The predictive ability of combined admission risk factors and combined intrapartum risk factors were compared using receiver operating characteristic curves in three groups of patients: nulliparas, multiparas, and patients with a prior cesarean section. Of 20,148 pregnancies admitted for delivery, 3,003 patients (15%) had second stage CD. Admission risk factors associated with need for second stage CD included advanced maternal age, gestational age>=41 weeks (aRR 1.57, 95% CI 1.43-1.72), obesity (aRR 1.99 95% CI 1.85-2.14) chronic hypertension and pre-gestational (aRR 2.35, 95% CI 1.97-2.79) or gestational diabetes (aRR 1.85, 95% CI 1.62-2.12). Intrapartum risk factors associated with need for second stage CD included type of induction, duration of first stage of labor (aRR 1.03 95% CI 1.02-1.04-nulliparous patients) and duration of pushing (aRR 1.08 95% CI 1.06-1.09-nulliparous patients). Among nulliparous patients, admission factors and intrapartum factors were both poor predictors of second stage CD, however admission factors performed significantly better than intrapartum factors (AUC 0.62 vs 0.59, p <0.01). Among multiparous women and patients with a prior cesarean, intrapartum factors were more predictive of second stage CD than admission factors (AUC0.58 vs AUC 0.67, p<0.01 and AUC 0.57 vs 0.67, p<0.01 respectively). Although overall limited in their predictive abilities, there are noteworthy clinical risk factors available at admission and intrapartum that are associated with second stage CD. Admission risk factors appear to perform better as a predictor in nulliparous patients, whereas intrapartum risk factors perform better in multiparas and patients with prior cesarean delivery.