Birthweight at Two Extremes: Reproductive Weathering and the Early-Life Structuring of Health Inequality by Race/Ethnicity-Nativity.

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Abstract

Racial/ethnic and nativity disparities in birthweight persist in the United States, yet less is known about how these inequalities vary across the maternal age distribution and at both extremes of birthweight distribution. Drawing on the weathering hypothesis, this study examines how race/ethnicity, nativity, and maternal age jointly shape the risk of low birthweight (LBW) and macrosomia. Utilizing 2024 National Vital Statistics System natality data (N = 2,839,258) and multinomial logistic regression, the analysis estimates risks of birthweight extremes relative to normal birthweight, focusing on interactions between race/ethnicity-nativity categories and maternal age groups.
Results indicate that US-born Black women exhibit the highest baseline risk of LBW, with risk increasing steeply at older maternal ages – a pattern consistent with the weathering hypothesis and the cumulative physiological toll of structural disadvantages. Foreign-born Black women and Hispanic women of either nativity also show accelerated age-related increases in LBW risk, particularly after age 30. Conversely, foreign-born White women demonstrate a persistent immigrant health advantage across age groups.
A novel contribution of this study is the identification of weathering patterns in macrosomia. While US-born White women exhibit the highest baseline risk of macrosomia, the protective advantages held by foreign-born Hispanic women erode with advancing age, showing convergence toward higher risk. Asian women exhibit relatively stable risk profiles across age groups. By extending weathering research to macrosomia, this study illustrates how structural inequalities create diverging destinies at the start of the life course, underscoring the need for policies that disrupt structural determinants of health inequalities at birth.

Author

• John Whesu, Case Western Reserve University