Association between maternal body composition during pregnancy and birth weight of offspring in pregnant women with gestational diabetes mellitus

Background: The relationship between maternal body composition and offspring birth weight remains controversial, and limited research has been conducted in gestational diabetes mellitus (GDM) patients. Therefore, this study aims to explore the association between the body composition of GDM patients and offspring birth weight. METHODS: Pregnant women diagnosed with GDM were enrolled and followed until delivery. Maternal body composition was assessed via bioelectrical impedance analysis during pregnancy. Multiple regression analysed associations between maternal body composition and offspring birth weight; restricted cubic spline (RCS) models examined potential nonlinearity. Results: This cohort study involved 929 pregnant women; 32 newborns were macrosomia.After covariate adjustment, offspring birth weight positively correlated with maternal total body water (TBW), intracellular fluid (ICF), extracellular fluid (ECF), fat mass (FM), fat-free mass (FFM), muscle mass (MM), protein, percent protein, minerals, and percent minerals in mothers with GDM. Multiple logistic regression showed that ECF increased the risk of macrosomia in GDM (OR:1.39, 95%CI:1.03-1.90). In the RCS model, n-shaped associations were found between the risk of macrosomia and maternal TBW, ICF, ECF, FFM, MM, protein, and minerals in GDM patients, while no significant association was observed for maternal FM. Conclusions： Although there is a positive correlation between the maternal body composition of pregnant women with GDM and the birth weight of their offspring, the association with the risk of macrosomia is not a simplistic linear relationship. Instead, when the body composition except FM reaches a certain critical threshold, there may be a reduction in the risk of macrosomia observed.