Maternal Diet Quality Assessed Using the Korean Healthy Eating Index and Risk of Small-for-Gestational-Age Infants: Findings from the Mothers and Children’s Environmental Health (MOCEH) Study

<b>Background</b>: Maternal diet quality during pregnancy may significantly influence fetal growth and birth weight. <b>Objectives</b>: This study aimed to assess the dietary quality of pregnant women in Korea and investigate its association with the risk of delivering a small-for-gestational-age (SGA) infant. <b>Methods</b>: A total of 1158 pregnant women and their newborns were recruited from the Mothers and Children's Environmental Health (MOCEH) 2006-2010 cohort. Maternal dietary intake during gestational weeks 12-28 was assessed using a validated food frequency questionnaire. The nutrient adequacy ratio (NAR), mean adequacy ratio (MAR), and Korean Healthy Eating Index (KHEI) were employed to evaluate dietary quality. Birth outcomes were obtained from hospital records, and logistic regression analyses were performed to examine associations between maternal dietary quality and SGA risk. <b>Results</b>: Higher KHEI scores were significantly associated with increased nutrient intake, with the exception of fat, and demonstrated a positive association with the NAR of 15 nutrients. After adjusting for covariates, women in the highest KHEI quartile exhibited a significantly lower risk of SGA birth than those in the lowest quartile (adjusted odds ratio: 0.448; 95% confidence interval: 0.201-0.997; P-for-trend = 0.031). <b>Conclusions</b>: Enhanced maternal diet quality, as measured using the KHEI, is associated with improved nutrient intake and a reduced risk of SGA births among Korean pregnant women. These findings underscore the need for public health strategies that promote high-quality diets during pregnancy to improve birth outcomes.