The Health Effects of Cesarean Delivery for Low-Risk First Births

Cesarean delivery for low-risk pregnancies is generally associated with worse health outcomes for infants and mothers. The interpretation of this correlation, however, is confounded by potential selectivity in the choice of birth mode. We use birth records from California, merged with hospital and emergency department (ED) visits for infants and mothers in the year after birth, to study the causal health effects of cesarean delivery for low-risk first births. Building on McClellan, McNeil, and Newhouse (1994), we use the relative distance from a mother’s home to hospitals with high and low c-section rates as an instrument for c-section. We show that relative distance is a strong predictor of c-section but is orthogonal to many observed risk factors, including birth weight and indicators of prenatal care. Our IV estimates imply that cesarean delivery causes a relatively large increase in ED visits of the infant, mainly due to acute respiratory conditions. We find no significant effects on mothers’ hospitalizations or ED use after birth, or on subsequent fertility, but we find a ripple effect on second birth outcomes arising from the high likelihood of repeat c-section. Offsetting these morbidity effects, we find that delivery at a high c-section hospital leads to a significant reduction in infant mortality, attributable to lower deaths among newborns with high rates of pre-determined risk factors.