Racial and ethnic disparities in low birthweight among urban unmarried mothers

We examined racial and ethnic disparities in low birthweight (LBW) among unmarried mothers and the extent to which demographic, economic, psychosocial, health, health care, and behavioral factors explain those disparities.

Using a sample of 2,412 non-marital births from a national urban birth cohort study, we estimated multiple logistic regression models to examine disparities in LBW between non-Hispanic white (NHW), non-Hispanic black (NHB), U.S.-born Mexican-origin (USMO), and foreign-born Mexican-origin (FBMO) mothers.

NHW mothers were almost as likely as NHB mothers to have LBW infants. USMO mothers had 60% lower odds and FBMO mothers had 57% lower odds than NHW mothers of having LBW infants. FBMO mothers had no advantage compared to USMO mothers. Controlling for prenatal health and behaviors substantially reduced the LBW advantages for USMO and FBMO mothers. The odds of LBW for NHB mothers relative to NHW mothers increased with the addition of the same covariates.

Racial and ethnic disparities in LBW among unmarried mothers--an economically disadvantaged population--do not mirror those in the general population. Prenatal health and behaviors are strongly associated with LBW in this group and explain a sizable portion of the Mexican-origin advantage. The lack of a significant black-white disparity in this group suggests that poverty plays an important role in shaping racial disparities in the general population. The finding that controlling for prenatal health and behaviors widens rather than narrows the racial disparity suggests that efforts to ameliorate black-white disparities in LBW should focus on social and health risks throughout the life course.