Women, Infants, and Children (WIC): Effect on Infant Feeding Practices and Children's Health and Well-Being

Year: 2007

Research Center: The Harris School of Public Policy Studies, University of Chicago

Investigator: Ziol-Guest, Kathleen M., and Daphne C. Hernandez

Institution: Harvard University

Project Contact:
Kathleen M. Ziol-Guest
Harvard University, Harvard School of Public Health
Department of Society, Human Development, and Health
Landmark Center West, Room 445-B
401 Park Drive
Boston, MA 02215
Phone: 617-384-8917


The Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) serves an important function. It safeguards the health of low-income women, infants, and children up to age 5 who are at nutritional risk by providing nutritious foods to supplement diets, information on healthy eating, referrals to health care, and breastfeeding promotion and counseling. However, despite the aim of addressing the nutritional and health needs of the low-income population, the impact on infant children’s health and nutrition remain poorly understood.

Existing research suggests that WIC is successful, namely that prenatal WIC participation improves birth outcomes, including reducing the incidence of low birth weight, increasing mean gestational age, and reducing prematurity and mortality. Overall findings indicate that prenatal WIC participants have better pregnancy and birth outcomes compared with low-income nonparticipant mothers. Additionally, empirical research suggests that the relationship between WIC participation and breastfeeding is negative. Very little empirical research examines the timing of prenatal WIC participation and whether it is WIC participation or when a mother begins receiving WIC that influences children’s health and feeding practices.

This study examined the association between WIC participation during the prenatal period and infant feeding practices and children’s health and well-being. It further examined the extent that timing of WIC participation (first, second, or third trimester entry) differentially impacted these outcomes.

Data for this study are drawn from the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B), a nationally representative cohort of children born in 2001 (children are sampled via registered births) who are followed from birth through kindergarten entry. The goal of the ECLS-B is to provide a comprehensive and reliable set of data to better understand children’s early development; their health care, nutrition, and physical well-being; their preparation for school; key transitions during the early childhood years; their experiences in early care and education programs plus kindergarten entry; and the manner in which their early experiences relate to their later development, learning, and experiences in school. The study, sponsored by the U.S. Department of Education National Center for Education Statistics, includes an oversampling of Asian/Pacific Islanders and American Indians, low-birth-weight infants, and twins. The sample is limited to children considered most likely to be WIC-eligible, namely those with annual reported household incomes less than 250 percent of the poverty threshold at the 9-month interview or those mothers who reported that Medicaid paid for all or some of their prenatal care.

The study examined two sets of outcomes: (1) infant feeding practices, including initiation of breastfeeding, duration of breastfeeding lasting longer than 4 months, and introduction of cow’s milk prior to 6 months of age; and (2) fetal growth, including extremely low birth weight, very low birth weight, low birth weight, high birth weight, term low birth weight, small for gestational age, and low 5-minute APGAR score.

Multivariate regression analysis and instrumental variable approaches were used to test the association between WIC participation and the outcomes. These models were constructed to account for the endogeneity of WIC participation.

Results from the analysis and infant feeding practices suggest that WIC participation is negatively associated with initiation of breastfeeding, with a mother who participated in WIC prenatally 5 percentage points less likely to initiate breastfeeding compared with a low-income mother who did not participate. WIC participation is also negatively associated with breastfeeding for at least 4 months. Further, WIC participants are 35 percent less likely to introduce cow’s milk to the infant’s diet prior to 6 months of age compared with WIC nonparticipants. In terms of when mothers entered the WIC program while pregnant, mothers who entered WIC during their first trimester are 6 percentage points less likely to initiate breastfeeding compared with those who did not use WIC during pregnancy. Further, mothers who began receiving WIC during their second trimester were 4 percentage points less likely to initiate breastfeeding than nonparticipants. Mothers who began WIC in their first trimester are also less likely than those who did not use WIC prenatally to breastfeed for at least 4 months. Finally, mothers who began receiving WIC during their second trimester were less likely to feed their child cow’s milk prior to 6 months of age compared with those mothers who never participated in WIC.

Findings from the analysis on fetal growth suggest that WIC participation is associated with a lower likelihood that the child was born with a very low birth weight. Specifically, those who participate are 26 percent less likely to be very low birth weight. Results examining the timing of WIC entry indicate that mothers who entered the WIC program in the third trimester are less likely to have children with lower birth weights.

Direct inquiries about this study to the Project Contact listed above.