Does WIC Reduce Prenatal Substance Use?

Year: 2004

Research Center: Institute for Research on Poverty, University of Wisconsin-Madison

Investigator: Waehrer, Geetha

Institution: Pacific Institute for Research and Evaluation

Project Contact:
Geetha Waehrer
Pacific Institute for Research and Evaluation
11710 Beltsville Drive, Suite 300
Calverton, MD
Phone: 301-755-2714


This study examines the effect of the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) on prenatal use of alcohol and tobacco of participating pregnant women. Previous research shows that small-scale interventions similar to those provided in a WIC clinic can have an effect on preventing or reducing prenatal smoking or drinking. Yet few studies have examined the impact of WIC education on prenatal substance use. This is an important issue since prenatal exposure to alcohol, drugs and tobacco is one of the leading preventable causes of birth defects, mental retardations, and neurodevelopmental disorders in the United States. Pregnant WIC participants exhibit these behaviors: 29 percent smoke during pregnancy, 16 percent drink alcohol, and 8 percent use marijuana. Such behaviors directly undermine WIC’s goal of improving birth outcomes of poor children.

The study also examines the effect of state policies towards pregnant substance abusers on both WIC participation and prenatal substance use. These policies—which range from supportive (e.g., treatment and/or education) to punitive (e.g., child welfare investigations, termination of parental rights over prenatally exposed children, civil retention in a drug treatment facility for prenatal drug use)—may affect the participation of pregnant women in public health services. Yet little is known about their effects. The research reviews whether these policies change rates of prenatal drinking or smoking or have the unintended consequence of keeping women away from needed social services, including WIC.

Data from the National Longitudinal Survey of Youth, 1979 (NLSY) are used to study the effect of WIC on prenatal smoking and drinking. NLSY data are supplemented with information on state policies towards pregnant substance users. These data are rich enough to allow two-stage estimation models that control, where necessary, for sample selection into the pool of WIC participants. County characteristics help identify WIC effects in the two-stage models. The analysis incorporates the presence of multiple sibling families in the NLSY and estimate WIC effects using fixed-effect models.

Study results indicate that WIC’s non-nutrition activities play a role in moderating prenatal drinking and smoking. The results were stronger for white mothers and for models of smoking reduction while pregnant. However, WIC participation did not result in complete abstinence from smoking or drinking for all pregnant WIC women. The results are consistent with the literature showing that brief interventions can have a positive but limited effect on maternal behavior for the duration of the pregnancy.

The results suggest that, for nonwhite mothers, the State requirements for prenatal drug testing may discourage the use of health services like WIC. Instead, States with education and prioritized treatment may be more successful at exposing pregnant women to WIC services, including its array of nutrition-related activities Although punitive State approaches have received much media attention, these policies may not be a major factor in WIC participation, though this result could be driven by the limited number of affected pregnancies in the data.

The study suggests that pregnancy is a “teachable moment” when pregnant women are responsive even to small interventions that appeal to their desire to have healthy children. WIC provides a unique opportunity to engage low-income women who are at higher risk for prenatal substance use and unfavorable birth outcomes. WIC appears to affect the behavior of pregnant women even though its nutrition education sessions are not required for the receipt of other benefits.