Racial Inequities in Birth Weight by Maternal Age Among College-Educated Mothers: The Role of Early Disadvantage

Introduction: Non-Hispanic Black infants experience disproportionately high risks of low birth weight compared with non-Hispanic White infants, particularly among mothers with high educational attainment and greater socioeconomic advantage. This study investigates how maternal early-life disadvantage contributes to ongoing racial birth weight inequities among U.S. college‒educated mothers, specifically declining birth weights with age among non-Hispanic Black mothers. Methods: Study analyses used cohort data from the National Longitudinal Study of Adolescent to Adult Health. Racial inequities in birth weight by maternal age and early-life disadvantage were assessed using completed reproductive histories among college-educated mothers at ages 33–44 years collected in 2016‒2018 and regression-based marginal standardization techniques. Early-life disadvantage was measured using a study-based composite measure of early-life concentrated poverty and social disadvantage in homes, neighborhoods, and schools, collected in previous waves. Primary analyses were completed in 2020‒2021. Results: Among non-Hispanic Black mothers who experienced high early-life disadvantage, a 1-year increase in maternal age at delivery was associated with lower birth weight by 26.07 g (95% CI= −48.74, −3.40). Similar declines were not found among non-Hispanic Black mothers with low early-life disadvantage. Non-Hispanic White mothers experienced increased birth weight with maternal age, 6.85 g (95% CI= −1.12, 14.82) per year, which did not significantly vary by early-life disadvantage. Conclusions: Early-life disadvantage modifies whether and how college-educated mothers experience birth weight decline with older age. The effects of early-life contexts and embedded racial inequities on maternal health inequities and differential weathering warrant further public health attention.