Association of maternal pre-pregnancy body mass index with resilience and prosociality of the offspring aged 6-7 years old: a population-based cohort study in Japan.

The association between maternal pre-pregnancy obesity and child behavior problems has been widely researched, leaving a gap in understanding the positive aspects of children's mental health. The present study aimed to investigate the association between maternal pre-pregnancy body mass index (BMI) and resilience and prosociality among 6-7 year-old children in Japan. A retrospective cohort study was conducted using data from the Adachi Child Health Impact of Living Difficulty (A-CHILD) study, a population-based study in 2017 and 2019 including all first-grade students in public schools in Adachi, Tokyo, Japan (n = 7328, response rate = 84.7%). Resilience and prosociality were measured by the Children's Resilient Coping Scale and the Strength and Difficulties Questionnaire, respectively. Maternal pre-pregnancy weight and height were reported based on the Mother and Child Health Handbook, and BMI was categorized as underweight (BMI < 18.5), normal weight (BMI 18.5-24.9), overweight (BMI 25.0-29.9), and obesity (BMI ≥ 30). Linear regression models were employed to control for covariates. Maternal pre-pregnancy obesity was found to be negatively associated with child resilience (coefficient: - 3.29; 95% CI - 6.42--0.15), while maternal underweight was negatively associated with child prosociality (coefficient: - 0.12; 95% CI - 0.24--0.005) compared to mothers of pre-pregnancy normal BMI. Perinatal factors, such as gestational weight gain, gestational age, and birth weight, did not mediate the association. Our findings suggest that maternal pre-pregnancy obesity is linked to decreased resilience and maternal underweight is linked to decreased prosociality in children aged 6-7 years. Maintaining an appropriate BMI range before pregnancy may be crucial for enhancing resilience and prosociality of offspring.