Born on the wrong side of the tracks: Exploring the causal effects of segregation on infant health.

Prior research has found that a high level of residential racial segregation, or the degree to which racial/ethnic groups are isolated from one another, is associated with worsened infant health outcomes, particularly among non-Hispanic (NH) Black infant populations. However, because exposure to segregation is non-random, it is unclear whether and to what extent segregation is causally linked to infant health. To overcome this empirical limitation, we leverage exogenous variation in the placement of railroad tracks in the 19th century to predict contemporary segregation, an approach first introduced by Ananat (2011). In alignment with prior literature, we find that residential segregation has statistically significant associations with negative birth outcomes among Black infant populations in the area. Using OLS methods underestimates the negative impacts of segregation on infant health. We fail to detect comparable effects on health outcomes among NH White infant populations. Further, we identify several key mechanisms by which residential segregation could influence health outcomes among Black infant populations, including lower access to prenatal care during the first trimester, higher levels of anti-Black prejudice, greater transportation barriers, and increased food insecurity. Given that poor birth outcomes have adverse effects on adults' health and well-being, the findings suggest that in-utero exposure to residential segregation could have important implications for Black-White inequality over the life course.