Associations between historically redlined districts and racial disparities in current obstetric outcomes

1. Historically redlined districts and racial discriminatory policies were associated with worse obstetrical outcomes including preterm birth 

2. Structural inequities and racial disparities had detrimental health effects, increased obstetric related morbidity, and mortality 

Evidence Rating Level: 2 (Good) 

Racial and ethnic disparities are prevalent in the United States with pregnancy related morbidity and mortality at a significantly higher rate among Black women. Preterm birth is no exception with Black women experiencing a preterm birth rate 50% higher than non-Hispanic white women. Previous studies have revealed socioeconomic factors, stress, and structural systemic racism contribute to these findings. One aspect that has not yet been studied extensively was the practise of redlining by the federal government’s Home Owners’ Loan Corporation (HOLC). This redlining, beginning in the 1930s was a form of overt racism where mortgages and properties were classified as either  « desirable » or « hazardous » based on the demographic living in the area. In these HOLC maps, «safety » was synonymous with « white » neighborhoods. This led to declining conditions in certain black communities while intergenerational wealth was perpetuated among white families. These historical inequities have influenced modern day home ownership and further exasperated health disparities. This study aimed to better understand the impacts of structural racism in the housing market and specifically modern obstetric outcomes. In order to do so, a retrospective cohort study was conducted with n= 199 088 live births between 2005-2017 in 15 historically redlined zip codes. These zip code regions were previously categorized by racially discriminatory criteria according to the 1940’s (HOLC) map. Within these regions, specifically in Finger Lakes, live births were analyzed from obstetric data systems to assess for preterm birth (gestation less than 37 weeks), neonatal morbidity, and mortality. Overall, the association of racially  discriminatory home loan practise continues to have detrimental effects on modern obstetric outcomes.  A total of n=64 804 live births occurred within 15 zip codes redlined by the HOLC grading map. Rates of preterm birth increased as the HOLC grades worsened, with the « hazardous » zip code having the highest overall rate of preterm births 427/3449 (12.38%). This was in stark contrast with historically defined « Best/Desirable » zip codes resulting in the lowest overall preterm birth rates at 217/2873 (7%) of births.  Furthermore, rates of periviable birth were 3-fold higher in the “Hazardous” zip codes compared to the “Desirable” ones (26 births [0.75%] vs 7 births [0.24%]). Naturally, this study was limited by potential confounding factors leading to preterm and periviable births. However, a strength of the study is that it did include a relatively large sample size, covering several cities, counties and HOLC zip codes. Overall, this study highlights that historic inequities are not as far in the past as we may have hoped. Rather, their intergenerational effects continue to impact obstetric outcomes today. The legacy of inequities and discrimination continue in the 21st century. 

Click to read the study in JAMA Obstetrics and Gynecology

Image: PD

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