Location, location, location: The role of geography in cesarean delivery rates in the US

The high rate of cesarean section deliveries in the United States is a pressing public health issue as cesarean deliveries in healthy mothers unnecessarily increase the risk of adverse outcomes for both mother and newborn.   Current literature acknowledges the existence of geographic distinctions in cesarean rates, but this phenomenon is not well understood beyond the notion of differing physician practice styles.  This study examines how geography - particularly relating to the availability of healthcare resources – may impact cesarean rates.

Using a commercially insured US population, we obtained administrative data on nearly one million deliveries between 2008 and 2013.  We identified counties with unusually high (over 43%) or low (below 28%) cesarean delivery rates.  Matched cohorts were created from each group using propensity score matching to control for maternal age, multiple gestation, and maternal risk factors.  Using these matched cohorts, we then compared socioeconomic and healthcare supply characteristics between the areas using chi squared tests.

Comparing geographic characteristics of each area, statistically significant associations were found between higher cesarean rates and higher concentrations of Obstetrician-Gynecologist physicians per female resident and hospital beds per resident.  There were also statistically significant associations between elevated cesarean rates and high household income levels, low concentrations of non-white residents, and lower average educational attainment.

These findings suggest that higher availability of Obstetrician-Gynecologist physicians and hospital beds in a region may play a significant role in higher rates of cesarean deliveries.  This relationship may help explain geographic variation in cesarean rates outside of maternal characteristics.