Association between maternal history of mental illness and neurodevelopment of children during the first 3 years: The Japan Environment and Children's Study

Aim The impact of maternal mental illness on children's neurodevelopment has been insufficiently investigated, particularly in large populations. In this study, we examined the association between maternal mental health history and child neurodevelopment during the first 3 years postpartum, using large‐scale data from the Japan Environment and Children's Study (JECS). Methods We analyzed data from 64,389 mother–offspring pairs enrolled in JECS. Maternal history of mental illness was assessed using questionnaires administered during early pregnancy. Child neurodevelopment was assessed at ages 1, 2, and 3 years by mothers or guardians using the Japanese version of the Ages and Stages Questionnaires, 3rd Edition (J‐ASQ‐3), across five domains. In this study, we employed multivariate logistic regression analysis. Results Children whose mothers have a history of mental illness exhibited significantly higher risks of developmental delays in gross motor skills and problem‐solving domains at age 1, and across all J‐ASQ‐3 domains at ages 2 and 3, compared to those whose mothers do not have such a history. Conclusion Our findings indicate that children born to mothers with a history of mental illness may exhibit early neurodevelopmental delays in gross motor skills and problem‐solving as early as age 1 year, potentially leading to broader neurodevelopmental impairments observed in later childhood. Additionally, childcare support aimed at enhancing neurodevelopment may be essential for mothers with a history of mental illness within the first year postpartum.