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


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.
Gueorguieva
Ralitza
R
Division of Biostatistics, Department of Epidemiology and Public Health, Yale University, 60 College St, Room 201, New Haven, CT 06520-8034, USA. ralitza.gueorguieva@yale.edu
Morse
Steven B
SB
Roth
Jeffrey
J
D000328:Adult; D005260:Female; D005431:Florida; D005865:Gestational Age; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D008484:Medicaid; D011203:Poverty; D011247:Pregnancy; D011256:Pregnancy Outcome; D011295:Prenatal Care / Q000706:statistics & numerical data*; D011632:Public Assistance; D018570:Risk Assessment; D014481:United States; D055815:Young Adult