Background 

The Special Supplemental Nutrition Program for 

Women, Infants, and Children (WIC) provides 

supplemental foods, nutrition education, 

breastfeeding support, and referral to other services 

for pregnant and postpartum women, and infants and 

young children. The objectives of the program 

include but are not limited to: improving fetal growth 

and development, improving the health and 

development of infants and young children, and 

increasing access to needed services. This report 

summarizes the research literature published since the 

last major review of the effectiveness of WIC in 

meeting these objectives.1

 

Pregnancy and Birth Outcomes 

This review uncovered 15 studies conducted since the 

last review that evaluated WIC participation, 

pregnancy, and birth outcomes. Research on birth 

outcomes typically focused on birth weight, measures 

of gestational age, and measures of fetal growth such 

as small for gestational age or term low birth weight. 

The majority of the research found that participation 

in WIC is positively associated with gestational age 

and mean birth weight. Estimates of low and very 

low birth weight, unadjusted for gestational age, 

suggest substantial improvements associated with 

WIC. The association between WIC participation and 

fetal growth, however, was less consistent, with weak 

or no associations identified. 

Infant Feeding Practices 

This research uncovered 13 studies conducted since 

the last review that evaluated WIC participation and 

infant feeding practices. These studies typically 

focused on breastfeeding initiation, duration, and 

exclusivity, and the introduction of infant formula. 

Overall, the studies suggested lower breastfeeding 

rates among WIC participants; 11 of 13 studies found 

either negative or no association between WIC 

participation and breastfeeding. One study, however, 

found a positive association between WIC 

participation and breastfeeding initiation. Another 

study cited evidence that providing infant formula 

through WIC delays the introduction of cow’s milk 

into infants’ diets. 

Infant and Child Dietary Intake, Food Security, 

and Related Outcomes 

This review uncovered 16 studies conducted since the 

last review that evaluated WIC participation and 

infant and child dietary intake, food security, and 

related outcomes. These studies also included data 

on diet quality, knowledge of infant feeding practices, 

and food labeling behaviors. Overall, the studies 

suggested that WIC participation is associated with 

improved diets, including increased iron density, 

fewer added sugars, and a greater variety of foods. 

 Infant and Child Growth Outcomes 

This review uncovered seven studies conducted since 

the last review that evaluated WIC participation and 

infant and child growth outcomes. The most 

commonly considered outcome was likelihood of 

being obese. Overall, the evidence was mixed. One 

study concluded WIC participants tended to be lighter 

and shorter and two studies suggested significant 

reductions in the risk of being overweight among 

WIC participants. Another study found weight 

differences by race for WIC participants. The 

remaining studies found no consistent evidence of a 

relationship between WIC participation and weight. 

Child Immunization 

This review uncovered only three studies conducted 

since the last review that evaluated WIC participation 

and child immunization. Two studies concerned the 

up-to-date status of immunizations among children 

ages 19 to 35 months and were largely inconclusive. 

One of the two studies found no significant 

association and one found WIC participants were 

more likely to be vaccinated. The final study 

considered WIC participation and the hepatitis A 

Office of Research and Analysis January 2012 

EFFECTS OF THE SPECIAL SUPPLEMENTAL NUTRITION PROGRAM 

FOR WOMEN, INFANTS, AND CHILDREN (WIC): A REVIEW OF 

RECENT RESEARCH
vaccine. These findings suggested that WIC 

participants had a higher rate of vaccination against 

hepatitis A at age 1. 

 Infant and Child Utilization of Health Care 

Services and Related Costs 

This review uncovered six studies conducted since the 

last review that evaluated WIC participation and 

infant and child utilization of health care services and 

related costs. Three studies evaluated the association 

between WIC and preventative care that included 

common childhood illnesses, Medicaid expenditures, 

possible cost savings related to WIC participation, 

and dental care. In general, WIC participation was 

associated with greater utilization of health care and 

curative health services including preventative and 

restorative dental care. The greater utilization of 

services was often associated with higher Medicaid 

costs. 

Child Health and Socioemotional and Cognitive 

Development 

This review uncovered seven studies conducted since 

the last review that evaluated WIC participation and 

child health and development. Two studies considered 

childhood morbidity, four evaluated children’s 

general health, and one considered cognitive, motor, 

and socioemotional abilities. In general, the studies 

found no clear evidence of an association between 

WIC participation and child health outcomes. 

More Information 

Effects of the Special Supplemental Nutrition 

Program for Women, Infants, and Children (WIC): A 

Review of Recent Research2 is available online: 

http://www.fns.usda.gov/ora/MENU/Published/WIC/

WIC.htm. Additional information on the WIC 

Program is available at: http://www.fns.usda.gov/wic/

 

1

Fox, M., W. Hamilton, and B. Lin. Effects of Food Assistance and Nutrition and Health: Volume 3, 

Literature Review, Food Assistance and Nutrition Research Report No. 19-3, USDA, ERS, October 2004. 

Available at http://www.ers.usda.gov/Publications/FANRR19-3/

2

 Colman, S., I. P. Nichols-Barrer, J. E. Redline, B. L. Devaney, S. V. Ansell, and T. Joyce. 2012. Effects of 

the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC): A Review of Recent 

Research. 

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