OBJECTIVE: To evaluate maternal and neonatal safety measures in a large-scale quality improvement program associated with reductions in nulliparous, term, singleton, vertex cesarean delivery rates.

METHODS: This is a cross-sectional study of the 2015–2017 California Maternal Quality Care Collaborative (CMQCC) statewide collaborative to support vaginal birth and reduce primary cesarean delivery. Hospitals with nulliparous, term, singleton, vertex cesarean delivery rates greater than 23.9% were solicited to join. Fifty-six hospitals with more than 119,000 annual births participated; 87.5% were community facilities. Safety measures were derived using data collected as part of routine care and submitted monthly to CMQCC: birth certificates, maternal and neonatal discharge diagnosis and procedure files, and selected clinical data elements submitted as supplemental data files. Maternal measures included chorioamnionitis, blood transfusions, third- or fourth-degree lacerations, and operative vaginal delivery. Neonatal measures included the severe unexpected newborn complications metric and 5-minute Apgar scores less than 5. Mixed-effect multivariable logistic regression model was used to calculate odds ratios (Ors) and 95% CIs.

RESULTS: Among collaborative hospitals, the nulliparous, term, singleton, vertex cesarean delivery rate fell from 29.3% in 2015 to 25.0% in 2017 (2017 vs 2015 adjusted OR [aOR] 0.76, 95% CI 0.73–0.78). None of the six safety measures showed any difference comparing 2017 to 2015. As a sensitivity analysis, we examined the tercile of hospitals with the greatest decline (31.2%–20.6%, 2017 vs 2015 aOR 0.54, 95% CI 0.50–0.58) to evaluate whether they had greater risk of poor maternal and neonatal outcomes. Again, no measure was statistically worse, and the severe unexpected newborn complications composite actually declined (3.2%–2.2%, aOR 0.71, 95% CI 0.55–0.92).

CONCLUSION: Mothers and neonates participating in a large-scale Supporting Vaginal Birth collaborative had no evidence of worsened birth outcomes, even in hospitals with large cesarean delivery rate reductions, supporting the safety of efforts to reduce primary cesarean delivery using American College of Obstetricians and Gynecologists and Society for Maternal-Fetal Medicine guidelines and enhanced labor support.