WIC participation and pregnancy outcomes: Massachusetts Statewide Evaluation Project.

The effects of WIC prenatal participation were examined using data from the Massachusetts Birth and Death Registry. The birth outcomes of 4,126 pregnant women who participated in the WIC program and gave birth in 1978 were compared to those of 4,126 women individually matched on maternal age, race, parity, education, and marital status who did not participate in WIC. WIC prenatal participants are at greater demographic risk for poor pregnancy outcomes compare to all women in the same community. WIC participation is associated with improved pregnancy outcomes, including, a decrease in low birthweight (LBW) incidence (6.9 per cent vs 8.7 per cent) and neonatal mortality (12 vs 35 deaths), an increase in gestational age (40.0 vs 39.7 weeks), and a reduction in inadequate prenatal care (3.8 per cent vs 7.0 per cent). Stratification by demographic subpopulations indicates that subpopulations at higher risk (teenage, unmarried, and Hispanic origin women) have more enhanced pregnancy outcomes associated with WIC participation. Stratification by duration of participation indicates that increased participation is associated with enhanced pregnancy outcomes. While these findings suggest that birth outcome differences are a function of WIC participation, other factors which might distinguish between the two groups could also serve as the basis for alternative explanations.