Declining violence and improving birth outcomes in the US: Evidence from birth certificate data.

The decline in crime that occurred in the last decade of the 20th century was one of the most important societal changes in recent US history. In this paper, we leverage the sharp decline in violence that began in the 1990s to estimate the relationship between county-level murder rates and individual-level birth outcomes for Black, Hispanic, and White mothers. Using the FBI's Uniform Crime Reporting data from 1992 to 2002 and individual-level data from more than 30,000,000 US birth certificates, we employ two-way fixed effects models with a rich set of controls to compare births to similar women in the same county who experienced different crime rates during their pregnancies. Elevated murder rates are associated with substantially higher risks of low birth weight for White mothers, low birth weight and small for gestational age among Black mothers, and small for gestational age among Hispanic mothers. Sensitivity analyses show that the existence of confounders that would invalidate these inferences is highly unlikely, suggesting that we have identified causal relationships, even if some uncertainty about the precision of our estimates remains. These findings have potential implications for prenatal and postpartum care, and they add to a growing body of evidence showing that the "Great American Crime Decline" was strongly linked to improved outcomes among groups that experienced the steepest declines in violence.