Pregravid body mass index is associated with early introduction of complementary foods

To determine whether women who entered pregnancy overweight or obese were less likely to follow American Academy of Pediatrics guidelines for introducing complementary foods to infants after 4 months of age. In addition, we explored whether psychological factors accounted for any of the effect of pregravid body mass index on age of complementary food introduction.

A prospective cohort study from 2001 to 2005 that recruited pregnant women between 15 to 20 gestational weeks with follow-up through 12 months postpartum from University of North Carolina hospitals (n=550).

Multinomial models were used to estimate relative risk ratios. The outcome was age of complementary food introduction, categorized as younger than 4 months of age, 4 to 6 months, and 6 months or later (referent). Maternal body mass index was categorized as underweight (<18.5), normal weight (18.5 to 24.9), and overweight/obese (≥25). A series of regression analyses tested mediation by psychological factors measured during pregnancy (depressive symptoms, stress, and anxiety).

More than a third of the study population (35.7% of 550) entered pregnancy overweight/obese. The majority of participants (75.3%) introduced foods to their infants between 4 and 6 months of age. Compared with normal-weight women, those who were overweight/obese before pregnancy were more likely (relative risk ratios=2.22 [95% CI 1.23 to 4.01]) to introduce complementary foods before the infant was 4 months old, adjusting for race, education, and poverty status. Depressive symptoms, stress, and anxiety did not account for any of the effect of pregravid overweight/obesity on early food introduction.

The results suggest that overweight and obese women are more likely to introduce complementary foods early and that psychological factors during pregnancy do not influence this relationship. Future studies need to explore why overweight/obese women are less likely to meet the American Academy of Pediatrics recommendations for the introduction of complementary food.