Background: The Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) is intended to improve maternal and child health outcomes. In 2009, the WIC food package changed to better align with national nutrition recommendations.
Purpose: To determine whether WIC participation was associated with improved maternal, neonatal-birth, and infant-child health outcomes or differences in outcomes by subgroups and WIC enrollment duration.
Data sources: Search (January 2009 to April 2022) included PubMed, Embase, CINAHL, ERIC, Scopus, PsycInfo, and the Cochrane Central Register of Controlled Trials.
Study selection: Included studies had a comparator of WIC-eligible nonparticipants or comparison before and after the 2009 food package change.
Data extraction: Paired team members independently screened articles for inclusion and evaluated risk of bias.
Data synthesis: We identified 20 observational studies. We found: moderate strength of evidence (SOE) that maternal WIC participation during pregnancy is likely associated with lower risk for preterm birth, low birthweight infants, and infant mortality; low SOE that maternal WIC participation may be associated with a lower likelihood of inadequate gestational weight gain, as well as increased well-child visits and childhood immunizations; and low SOE that child WIC participation may be associated with increased childhood immunizations. We found low SOE for differences in some outcomes by race and ethnicity but insufficient evidence for differences by WIC enrollment duration. We found insufficient evidence related to maternal morbidity and mortality outcomes.
Limitation: Data are from observational studies with high potential for selection bias related to the choice to participate in WIC, and participation status was self-reported in most studies.
Conclusion: Participation in WIC was likely associated with improved birth outcomes and lower infant mortality, and also may be associated with increased child preventive service receipt.
Primary funding source: Agency for Healthcare Research and Quality. (PROSPERO: CRD42020222452).