Association between prepregnancy and newborn body mass index

Abstract Objectives: to investigate the association between prepregnancy body mass index (BMI) and newborns’ (NB) BMI. Methods: cohort study with 1,365 pregnant women and their newborns from the BRISA survey (Brazilian Ribeirão Preto and São Luís Birth Cohort Studies) in São Luís-MA. Prepregnancy BMI was self-reported, and newborns’ BMI was estimated using the weight and length measured at birth. A directed acyclic graph (DAG) was developed to identify the adjustment variables. The association between the prepregnancy BMI and newborns’ BMI were analyzed using multiple linear and Poisson regression with robust variance estimation. Results: NBs had 13.4±1.7kg/m2 average BMI at birth. In the linear analysis, we observed that as the prepregnancy BMI increases, the NBs BMI also increases (ß=0.07; CI95%=0.05–0.09;p<0.001). Newborns of mothers with prepregnancy overweight were 3.58 times more likely to be overweight. Conclusion: prepregnancy BMI can affect newborn’s BMI early. Thus, women planning to become pregnant should consider conducting nutritional planning to maintain or obtain a healthy weight to minimize the risk of overweight for the newborn.