Association of prenatal participation in a public health nutrition program with healthy infant weight gain.

Abstract

We tested the hypothesis that early enrollment in the Special Supplemental Nutrition Program for Women, Infants and Children (WIC) is associated with a reduced risk of rapid infant weight gain (RIWG). We used a longitudinal cohort of mother-infant pairs (n = 157,590) enrolled in WIC in New York State from 2008 to 2009 and estimated the odds of RIWG, defined as a 12-month change in weight-for-age z score of more than .67, comparing infants of mothers enrolled during the first, second, or third trimester of pregnancy with those who delayed enrollment until the postpartum period. After adjusting for potential confounders, the odds of RIWG (odds ratio [OR] = 0.76; 95% confidence interval [CI] = 0.74, 0.79) were significantly lower for infants of women enrolling during the first trimester versus postpartum. Birth weight-for-gestational-age z score (OR = 0.33; 95% CI = 0.32, 0.33) attenuated the estimate of prenatal versus postpartum enrollment (OR = 0.92; 95% CI = 0.88, 0.95; first-trimester enrollees). The results demonstrate that prenatal WIC participation is associated with reduced risk of RIWG between birth and age 1 year. Improved birth weight for gestational age may be the mechanism through which early prenatal WIC enrollment protects against RIWG.