Maternal protein intake in early pregnancy and child development at age 3 years

Background: The current study aimed to assess the association between low maternal protein intake during pregnancy and child developmental delay at age 3 years. Methods: This research used data obtained from the Japan Environment and Children’s Study. In total, we analyzed 77,237 mother–child pairs. Dietary intake was assessed using the Food Frequency Questionnaire. Developmental outcomes at age 3 years were evaluated with the Japanese version of the Ages and Stages Questionnaire, Third Edition. A multivariate logistic regression analysis was performed to assess the association between maternal protein intake during pregnancy and child development delays at age 3 years. Results: Based on the protein-to-total energy intake ratio during early pregnancy, the participants were categorized into three groups: <9.39% (>2 standard deviation below the mean), the severely low protein (SLP) group; 9.39–<13%, the low protein group; and ≥13%, the normal protein group. After adjusting for potential confounding factors, SLP intake was found to be significantly correlated with a higher risk of developmental delay according to the communication, fine motor and problem-solving skill domains. Conclusions: SLP intake caused by inadequate diet during early pregnancy was associated with a higher risk of child developmental delay at age 3 years. Impact: Animal studies have shown that maternal protein restriction during pregnancy and lactation causes abnormal brain development among offspring.Birth cohort studies to date have not assessed the effects of maternal low protein exposure during pregnancy on child development.Severely low protein intake during early pregnancy was associated with a higher risk of child developmental delay at age 3 years.Since nutritional imbalance in early pregnancy affects not only fetal growth but also postnatal neurodevelopment, nutritional management before pregnancy is considered important.