Associations between Historical Redlining and the Risk of Pregnancy Complications and Adverse Birth Outcomes in Massachusetts, 1995-2015

Objective: To assess the impact of historical redlining on the risk of pregnancy complications and adverse birth outcomes in Massachusetts (MA) from 1995 to 2015. Methods: In total, 288,787 pregnant people from the MA Birth Registry had information on parental characteristics, pregnancy factors, and redlining data at parental residences at the time of delivery. Historic redlining data were based on MA Home Owners' Loan Corporation (HOLC) security maps, with grades assigned (A "best," B "still desirable," C "definitely declining," and D "hazardous"). We used covariate-adjusted binomial regression models to examine associations between HOLC grade and each chronic condition and pregnancy/birth outcome. Results: Living in HOLC grades B through D compared with A was associated with an increased risk of entering pregnancy with chronic conditions and adverse pregnancy/birth outcomes. The strongest associations were seen with pregestational diabetes (adjusted risk ratio [RR] Grade D: 1.7, 95% confidence interval [CI]: 1.3, 2.4) and chronic hypertension (adjusted RR Grade D: 1.5, 95% CI: 1.1, 1.9). Conclusions: Historical redlining policies from the 1930s were associated with adverse pregnancy outcomes and chronic conditions; associations were strongest for chronic conditions in pregnancy.