Relationships of pregnancy and postpartum diet quality with offspring birth weight and weight status through 12 months

OBJECTIVE: This study examined relationships of maternal pregnancy and postpartum diet quality with infant birth size and weight status indicators through 12 months and tested whether breastfeeding duration modifies these associations. METHODS: In the Pregnancy Eating Attributes Study (PEAS), dietary intake was assessed six times in 458 mothers who were followed from early pregnancy through 12 months postpartum (2014-2018). Logistic and linear mixed models estimated relationships of pregnancy and postpartum diet quality (Healthy Eating Index [HEI]) with offspring who were large-for-gestational-age (LGA) at birth, as well as BMI z score (BMIz) and weight-for-length z score (WFLz) at birth, 6 weeks, 6 months, and 12 months. RESULTS: Pregnancy HEI was inversely related to LGA (odds ratio [OR] = 0.95, 95% CI: 0.92 to 0.98); HEI was also inversely related to WFLz (β = -0.01, 95% CI: -0.02 to -0.002) and BMIz (β = -0.009, 95% CI: -0.02 to -0.0009) from birth through 12 months. Postpartum HEI was inversely related to WFLz (β = -0.01, 95% CI: -0.02 to -0.0009) and BMIz (β = -0.008, 95% CI: -0.02 to 0.0007) in infants who were breastfed for at least 6 months, but not in those who were breastfed for a shorter duration. CONCLUSIONS: Maternal diet quality during pregnancy (and during postpartum in mothers who breastfed for a longer duration) was inversely related to LGA and weight status indicators from birth through 12 months. Increasing maternal diet quality may have use for promoting healthy infant weight development.