There is quite a lot of controversy surrounding the immense variation in c-section rates depending on hospital. Cesarean delivery rates for low risk women vary 3 fold across hospitals in the US. This variation was not previously explained by differences in patient populations. A new study in the American Journal of Obstetrics and Gynecology (here) offers additional information on the patient population such as ethnicity subgroups and pre-pregnancy obesity, in understanding variation in cesarean section rates.
The authors of the article collected retrospective data using Florida’s linked birth certificates and hospital discharge records. They collected data from over 400,000 first time pregnancies with one baby in the head-down position, that resulted in term live births in 122 nonmilitary hospitals. C-section rates varied from 13 to 47% by hospital. Multiple factors increased risk of a c-section, such as age over 35 years and BMI over 30, but even accounting for these individual factors, hospital geographic location accounted for 40% of variation.
The detailed data set even demonstrated the vast variation within one ethnic group. Because Florida has a large Hispanic population, the data included whether Hispanic women were of Mexican, Cuban, Puerto Rican, or other ancestry. Mexican women are less likely to have a c-section than Cuban or Puerto Rican women. Variation within ethnic subgroups is a largely un-explored factor in the variation in pregnancy outcomes.
There have also been accusations of unfair practices and that OBGYNs perform c-sections at 5PM so they don’t have to stay late. Some of the most interested data from this study showed the differences in cesarean delivery rates by a variety of variables, including time of day and weekday versus weekend. Adjusted risk of a c-section was no different during the weekdays as on weekends. And, the time women were most likely to have a c-section was 8 PM to midnight, certainly not the most convenient time in my calendar!