Prenatal Diet and Infant Growth From Birth to Age 24 Months.

Importance: Being born either small for gestational age (SGA) or large for gestational age (LGA) and experiencing rapid or slow growth after birth are associated with later-life obesity. Understanding the associations of dietary quality during pregnancy with infant growth may inform obesity prevention strategies.

Objective: To evaluate the associations of prenatal dietary quality according to the Healthy Eating Index (HEI) and the Empirical Dietary Inflammatory Pattern (EDIP) with infant size at birth and infant growth from birth to age 24 months.

Design, setting, and participants: This cohort study used data from birthing parent-child dyads in 8 cohorts participating in the Environmental influences on Child Health Outcomes program between 2007 and 2021. Data were analyzed from March 2021 to August 2024.

Exposures: The HEI and the EDIP dietary patterns.

Main outcomes and measures: Outcomes of interest were infant birth weight, categorized as SGA, reference range, or LGA, and infant growth from birth to ages 6, 12, and 24 months, categorized as slow growth (weight-for-length z score [WLZ] score difference <-0.67), within reference range (WLZ score difference -0.67 to 0.67), or rapid (WLZ score difference, >0.67).

Results: The study included 2854 birthing parent-child dyads (median [IQR] maternal age, 30 [25-34] years; 1464 [51.3%] male infants). The cohort was racially and ethnically diverse, including 225 Asian or Pacific Islander infants (7.9%), 640 Black infants (22.4%), 1022 Hispanic infants (35.8%), 664 White infants (23.3%), and 224 infants (7.8%) with other race or multiple races. A high HEI score (>80), indicative of a healthier diet, was associated with lower odds of LGA (adjusted odds ratio [aOR], 0.88 [95% CI, 0.79-0.98]), rapid growth from birth to age 6 months (aOR, 0.80 [95% CI, 0.37-0.94]) and age 24 months (aOR 0.82 [95% CI, 0.70- 0.96]), and slow growth from birth to age 6 months (aOR, 0.65 [95% CI, 0.50-0.84]), 12 months (aOR, 0.74 [95% CI, 0.65-0.83]), and 24 months (OR, 0.65 [95% CI, 0.56-0.76]) compared with an HEI score 80 or lower. There was no association between high HEI and SGA (aOR, 1.14 [95% CI, 0.95-1.35]). A low EDIP score (ie, ≤63.6), indicative of a less inflammatory diet, was associated with higher odds of LGA (aOR, 1.24 [95% CI, 1.13-1.36]) and rapid infant growth from birth to age 12 months (aOR, 1.50 [95% CI, 1.18-1.91]) and lower odds of rapid growth to age 6 months (aOR, 0.77 [95% CI, 0.71-0.83]), but there was no association with SGA (aOR, 0.80 [95% CI, 0.51-1.25]) compared with an EDIP score of 63.6 or greater.

Conclusions and relevance: In this cohort study, a prenatal diet that aligned with the US Dietary Guidelines was associated with reduced patterns of rapid and slow infant growth, known risk factors associated with obesity. Future research should examine whether interventions to improve prenatal diet are also beneficial in improving growth trajectory in children.