Poor diet quality in pregnancy is associated with increased risk of excess fetal growth: A prospective multi-racial/ethnic cohort study

Abstract

Background: Nutritional perturbations during pregnancy may impact fetal and long-term childhood growth, although there are limited data on overall diet quality. We investigated whether diet quality, measured by the Healthy Eating Index-2010 (HEI-2010), during pregnancy was related to birthweight z-score (BWZ) and the clinically relevant birth outcomes of large- and small-for-gestational age (LGA and SGA). Methods: In a prospective cohort of 2269 multi-racial/ethnic women from the Pregnancy Environment and Lifestyle Study (2014-2017), dietary intake was assessed by a food frequency questionnaire during early pregnancy. Offspring BWZ and LGA or SGA were derived based on gestational age-, sex-, and racial/ethnic-specific birthweight distributions. Multivariable linear and Poisson regression with robust standard errors were used. Results: About 80% of women did not achieve good diet quality (HEI-2010 < 80). After adjusting for covariates, infants born to women in the lowest vs highest quartile of HEI-2010 (37.5-64.4 vs 78.7-94.2) had a 0.12 standard-deviation [95% confidence interval (CI) 0.01-0.23, P-for-trend ¼ 0.023] greater BWZ and 1.76-fold (1.08-2.87, P-for-trend ¼ 0.037) increased risk of LGA. No association was observed between HEI-2010 and SGA. Per-5point substitution of the reversely coded empty calories component score with the whole grains component score in the HEI-2010 was related to a 25% (95% CI 0.66-0.86) lower risk of LGA. Conclusions: Poor diet quality in pregnancy was associated with higher birthweight and increased risk of LGA independent of maternal obesity and other covariates. Substitution of empty calories with whole grains may mitigate the risk of excess fetal growth. Our findings may inform potential prevention strategies and dietary guidelines for pregnant women.