Prematurity and race account for much of the interstate variation in infant mortality rates in the United States.

Objective: To assess the correlation between infant mortality and extreme prematurity by state.

Study Design: This ecological study included data on 28,526,534 infants from 2007 to 2013 in all 50 US states and DC using CDC WONDER linked birth and infant death records. Regression analyses determined the correlation between infant and neonatal mortality rates and the proportion of extremely preterm, extremely low birth weight, and black births by state.