What Links Maternal Prepregnancy BMI to Early Childhood BMI: A Serial Mediation Analysis

Objective The aim of this study was to explore the potential impact of maternal gestational weight gain (GWG), infant birth weight, and postnatal weight change (ΔWAZ) on the relationship between maternal prepregnancy BMI (ppBMI) and childhood BMI. Methods This retrospective cohort study analyzed a data set from Wuhan, China. The mediation effect of targeted mediators on the association between maternal BMI and childhood BMI at the age of 2 years was analyzed. Results In the mediation model comprising maternal GWG, infant birth weight, and the first‐6‐month ΔWAZ as mediators of the association between ppBMI and children's BMI, the per unit increase in ppBMI resulted in a 0.01‐kg/m2 increase in children's BMI, through all three mediators. For the model comprising infant birth weight and the first‐6‐month ΔWAZ as mediators but maternal GWG as a moderator, the indirect effects of the first‐6‐month ΔWAZ on the relationship between ppBMI and childhood BMI was 0.0018 higher when maternal GWG increased from average values to 1 SD above the average values. Conclusions Maternal GWG, infant birth weight, and the first‐6‐month ΔWAZ mediated the effects of maternal ppBMI on children's BMI. Interventions targeting these factors can mitigate the risk of childhood obesity.