The Influence of County Contexts on Preterm Births Among Latina Mothers in the US

Preterm birth (PTB), defined as delivery before 37 weeks of gestation, is a significant public health issue, with implications for newborns, families, and society. The residential contexts in which mothers live may, in part, shape their risk of delivering preterm. Although ethnic enclaves-residential settings with a large concentration of people from the same ethnic group-exist within counties, little is known about how different county contexts shape PTB. This national study investigates the association between living in distinct county types and preterm births among Latina mothers (N = 1,084,867). Data are from 2 years (2017-2018) of US birth records merged with demographic and policy datasets. A county-level classification scheme that integrates social (i.e., Latino ethnic density, immigrant concentration), economic (i.e., socioeconomic indicators), and geography-related (i.e., suburban and urban) county characteristics was used to represent different areas. We fit multiple logistic regression models, adjusting for individual, community, and structural-level covariates, and found significant differences in PTB across county types (p < 0.001). In fully adjusted models, Latina mothers in almost all county types reported 5-25% higher odds of PTB than their counterparts in suburban counties with medium Latino concentration, high immigrant density, and low economic disadvantage. These areas were distinct from the high-disadvantage suburban counties with a large share of Latinos and immigrants, where Latina mothers experienced the highest likelihood of PTB (OR = 1.25, 95% CI 1.20, 1.30). County-level social, economic, and geography-related determinants interact, shaping Latina mothers' PTB risk. To ensure healthy environments for all, initiatives that bolster local communities are needed.