One health maintenance organization's experience: obstetric costs depend more on staffing patterns than on mode of delivery.

The objective of this study was to examine whether the mode of obstetric delivery is related to resource costs, case mix, maternal length of stay, or neonatal morbidity. Patients (27,289) who delivered babies at nine hospitals within one health maintenance organization in 1989 were the source of data. Case-mix adjustment and outcome measures (maternal length of stay and neonatal morbidity) were computed from discharge abstract indicators, whereas cost data (direct professional hours) came from departmental financial reports. Costs and outcomes were adjusted by regression analysis for differences in case mix and then compared by correlation analysis. Neither adjusted nor unadjusted cesarean-section rates and obstetric cost per case were significantly correlated over the range of observed cesarean-section rates. Aggregate cesarean-section rates and outcome indicators were also statistically unrelated. Cesarean-section rate variation across hospitals was unrelated to the observed variation in obstetric costs, which were closely related to variations in staffing and less closely to differences in patient case mix and scale.