Objective: The purpose of this study was to examine cesarean delivery morbidity and its predictors in the United States.

Study design: We used 2000-2011 Nationwide Inpatient Sample data to identify cesarean deliveries and records with 12 potential cesarean delivery complications, including placenta accreta. We estimated cesarean delivery morbidity rates and rate changes from 2000-2011, and fitted Poisson regression models to assess the relative incidence of morbidity among repeat vs primary cesarean deliveries and explore its predictors.

Results: From 2000-2011, 76 in 1000 cesarean deliveries (97 in 1000 primary and 48 in 1000 repeat cesarean deliveries) were accompanied by ≥1 of 12 complications. The unadjusted composite cesarean delivery morbidity rate increased by 3.6% only among women with a primary cesarean delivery (P < .001); the unadjusted rate of placenta accreta increased by 30.8% only among women with a repeat cesarean deliveries (P = .025). The adjusted rate of overall composite cesarean delivery morbidity decreased by 1% annually from 2000-2011 (P < .001). Compared with women with a primary cesarean delivery, those women who underwent a repeat cesarean delivery were one-half as likely (incidence rate ratio, 0.50; 95% CI, 0.49-0.50) to experience a complication, but 2.13 (95% CI, 1.98-2.29) times more likely to have a placenta accreta diagnosis. Both cesarean delivery morbidity and placenta accreta were positively associated with age >30 years, non-Hispanic black race/ethnicity, the presence of a chronic medical condition, and delivery in urban, teaching, or larger hospitals.

Conclusion: Overall, cesarean delivery morbidity declined modestly from 2000-2011, but placenta accreta became an increasingly important contributor to repeat cesarean delivery morbidity. Clinicians should maintain a high index of suspicion for abnormal placentation and make adequate preparations for patients who need cesarean deliveries.