(345) Association of county-level WIC enrollment and adverse pregnancy outcomes in the U.S. from 2016-2019

Using U.S. National Center for Health Statistics Natality data between 2016-2019, we conducted a longitudinal, county-level analysis. The exposure was the change in county-level WIC enrollment from 2016 to 2019 (increase [ >0%] versus no change or decrease [≤0%]) among those eligible for WIC (i.e., U.S. resident and Medicaid insured). APOs were measured in 2019, and included maternal (CD, HDP, GDM, ICU admission, and transfusion) and infant (PTB < 34 weeks, NICU admission, SGA, and LGA) measures. Hierarchical logistic regression was used and adjusted for baseline county-level mean WIC enrollment and APOs in 2016 and individual-level covariates, including mean age at delivery, and proportion of the population that self-identified as non-Hispanic White, had competed college education, and enrolled in prenatal care in the first trimester.

Results: Among 1,945,914 WIC-eligible nulliparous individuals from 3,120 U.S. counties, the county-level age-standardized rate of WIC enrollment decreased from 2016 (73.1%) to 2019 (66.1%) (average annual percent change, AAPC: -3.2%; 95% CI: -3.7, -2.9). WIC enrollment increased in 27.4% of counties. Compared with counties in which WIC enrollment decreased or did not change, counties in which WIC enrollment increased had lower rates of multiple maternal [GDM (aOR: 0.71; 95% CI: 0.57, 0.89), ICU admission (aOR: 0.47; 95% CI: 0.34, 0.65), transfusion (aOR: 0.68; 95% CI: 0.53, 0.88)], and infant [PTB (aOR 0.71; 0.56, 0.90); NICU admission (aOR: 0.77; 95% CI: 0.60, 0.97)] APOs.

Conclusion:

As a greater proportion of eligible nulliparous individuals within a county enrolled in WIC, the likelihood of APOs decreased. In an era where WIC enrollment has decreased and food and nutrition insecurity has increased, efforts are needed to increase WIC enrollment among eligible individuals in pregnancy.