The effect of the 2009 WIC revision on maternal and child health: A quasi-experimental study

Abstract

Background: The Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) is the largest U.S. nutrition program for low-income pregnant women. It was revised in 2009, with the goal of improving nutritional content of food packages, enhancing nutrition education, and strengthening breast feeding support. Few studies have assessed the effects of this revision on perinatal health.

Objectives: To investigate the impact of the revised WIC program on maternal and child health in a large, multi-state data set.

Methods: We conducted a quasi-experimental difference-in-differences analysis, comparing the pre/post changes among WIC recipients to changes among non-recipients. We adjusted for key sociodemographic covariates in multivariable linear models. We used data from the Pregnancy Risk Assessment Monitoring System (PRAMS) for 18 states from 2004 to 2017.

Results: The main analysis included 331,946 mother-infant dyads. WIC recipients were more likely to be younger, Black or Hispanic/Latina, unmarried, and of greater parity. The revised WIC program was associated with reduced likelihood of more-than-recommended GWG (-1.29% points, 95% confidence interval [CI] -2.03, -0.56) and increased likelihood of ever breast fed (1.18% points, 95% CI 0.28, 2.08). We also identified heterogeneous effects on GWG, with more pronounced associations among women 35 and older. There were no associations with foetal growth.

Conclusions: The revised WIC program was associated with improvements in women's gestational weight gain and infant breast feeding.

Keywords: PRAMS; United States; WIC program; infant health; maternal health; nutrition during pregnancy; policy analysis; quasi-experimental studies.

Figure 1.. Sample Selection Flowchart.

The Pregnancy Risk Assessment Monitoring System (PRAMS) dataset includes linked birth certificate and mothers’ survey responses. WIC indicates Special Supplemental Nutrition Program for Women, Infants, and Children.