The Supplemental Nutrition Program for Women, Infants, and Children and Birth Outcomes Among Hispanic Mothers in California: A Sibling Control Design.

Background: Participation in the Supplemental Nutrition Program for Women, Infants, and Children (WIC) during pregnancy appears to reduce risks of preterm birth and low birthweight. Many pregnant women who receive WIC benefits, however, also participate in Medicaid (Medi-Cal in California). This co-participation raises the question of whether WIC per se confers these perinatal health benefits.

Methods: We use a unique, sibling-linked dataset of California births to estimate birth outcomes relating to program receipt (i.e., No WIC or Medi-Cal; WIC alone; Medi-Cal alone; and WIC and Medi-Cal). We also contribute to the literature by focusing on Hispanic mothers who represent the largest fraction of births in California, as well as the highest proportion of WIC recipients in the state. We specifically assessed the relation of differential program receipt on preterm birth (< 37 weeks) and low birthweight (< 2500 g). We restrict our analytic sample to births between 2007 and 2015 (n = 942,274).

Results: Our sibling-control results show lower odds of low birthweight (OR: 0.82, 95% CI: 0.77, 0.87) and preterm birth (OR: 0.87, 95% CI: 0.83, 0.90) when Hispanic mothers receive WIC benefits during pregnancy compared to when the mothers do not receive WIC benefits. While births associated with receipt of both WIC and Medi-Cal also exhibit lower odds of preterm birth (OR: 0.86, 95% CI: 0.79, 0.92), the protective findings do not extend to low birthweight.

Conclusion: Our results extend previous work in other states and should stimulate additional research on whether participation in multiple means-tested programs reduce racial/ethnic disparities in adverse birth outcomes.