Cesarean section in term breech presentations: do rates of adverse neonatal outcomes differ by hospital birth volume?

To determine if risk of adverse neonatal outcomes among term breech infants delivered by cesarean section differs by volume of such births at the delivering hospital.

We conducted a population-based cohort study using Missouri linked birth and death certificate files. The study population included 10,106 singleton, term, normal birth weight infants in breech presentation delivered by cesarean section. Infants were linked to hospitals where delivered. These hospitals were divided into terciles (low, medium, and high volume) based on the median number of annual deliveries during 1993-1999. The primary outcome was presentation of at least one adverse neonatal outcome. Adjusted odds ratios and 95% confidence intervals (CI) were calculated using logistic regression analysis.

The rate of any adverse outcome was 17.8, 15.0, and 5.9 cases per 1,000 deliveries at low-, medium-, and high-volume hospitals, respectively. All component adverse outcomes occurred more frequently in low- or medium-volume hospitals than in high-volume hospitals. Compared to breech infants delivered at high-volume hospitals, those delivered at low-volume and medium-volume hospitals were 2.7 (CI 1.6, 4.5) and 2.4 (CI 1.4, 4.1) times, respectively, more likely to experience an adverse outcome after adjusting for significant confounders.

Prospective studies should explore the source of these risk differences.