Hospital volume and cesarean delivery among low-risk women in a nationwide sample.

OBJECTIVE: We sought to determine if hospital delivery volume was associated with a patient's risk for cesarean delivery in low-risk women. STUDY DESIGN: This study retrospectively examines a cohort of 1 657 495 deliveries identified in the 2013 Nationwide Readmissions Database. Hospitals were stratified by delivery volume quartiles. Low-risk patients were identified using the Society for Maternal-Fetal Medicine definition (n=845 056). A multivariable logistic regression accounting for hospital-level clustering was constructed to assess the factors affecting a patient's odds for cesarean delivery. RESULTS: The range of cesarean delivery rates was 2.4-51.2% among low-risk patients, and the median was 16.5% (IQR 12.8-20.5%). The cesarean delivery rate was higher in the top two-volume-quartile hospitals (17.4 and 18.2%) compared to the bottom quartiles (16.4 and 16.3%) (P<0.001). Hospital volume was not associated with a patient's odds for cesarean delivery after adjusting for patient and other hospital characteristics (P=0.188). CONCLUSION: Hospital delivery volume is not an independent predictor of cesarean delivery in this population.