Length of prenatal participation in WIC and risk of delivering a small for gestational age infant: Florida, 1996-2004

Matern Child Health J. 2009 Jul;13(4):479-88. doi: 10.1007/s10995-008-0391-8. Epub 2008 Jul 26.


Objective: To assess the association between length of prenatal participation in WIC and a marker of infant morbidity. By focusing on small for gestational age, we consider one of the possible pathways through which prenatal nutrition affects fetal growth.

Design/methods: The study sample consists of 369,535 matched mother-infant pairs drawn from all singleton live births in Florida hospitals from 1996 to 2004. All subjects received WIC and Medicaid-funded prenatal services during pregnancy. We controlled for selection bias on observed variables using a generalized propensity scoring approach and performed separate analyses by gestational age category to control for simultaneity bias.

Results: Ten percent increase in the percent of time in WIC was associated with 2.5% decrease (95% CI: 2.1-3.0%) in the risk of a full-term an SGA infant. The risk was also significantly decreased for very preterm and late preterm infants (29-33 and 34-36 weeks gestation) but not for extremely preterm infants (23-28 weeks gestation).

Conclusions: The observed small negative dose response relationship between percent of pregnancy spent in WIC and fetal growth restriction implies that longer participation in the program confers a small measure of protection against delivering an SGA infant.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adult
  • Female
  • Florida
  • Gestational Age*
  • Humans
  • Infant, Low Birth Weight*
  • Infant, Newborn
  • Medicaid
  • Poverty
  • Pregnancy
  • Pregnancy Outcome
  • Prenatal Care / statistics & numerical data*
  • Public Assistance*
  • Risk Assessment
  • United States
  • Young Adult