Maternal pre-pregnancy BMI and early childhood adiposity trajectories: longitudinal evidence from the Taiwan birth cohort study

Maternal overweight and gestational metabolic disorders are established risk factors for adverse pregnancy outcomes and may influence the risk of overweight or obesity in offspring. However, the extent to which these factors independently or jointly affect early childhood adiposity remains unclear, particularly in Asian populations. This study examined the independent and combined effects of maternal pre-pregnancy body mass index (BMI), gestational diabetes mellitus (GDM), hypertensive disorders of pregnancy (HDP), and excessive gestational weight gain (EGWG) on offspring adiposity, with an emphasis on population-level and policy implications. Data were derived from the Taiwan Birth Cohort Study (TBCS), a nationally representative longitudinal dataset of 20,764 mother–child pairs followed from birth to 66 months. Generalized estimating equation (GEE) models were used to analyze BMI trajectories across seven time points, and logistic regression estimated adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for childhood overweight and obesity at 66 months. Analyses were conducted in SAS 9.4; a two-sided p value < 0.001 was considered statistically significant. Children born to mothers with overweight or obesity showed persistently higher BMI trajectories and an earlier adiposity rebound than those of mothers with normal weight. At 66 months, adjusted ORs for overweight or obesity (OWOB) were 1.39 (95% CI 1.22–1.58) and 1.49 (95% CI 1.27–1.74) for maternal overweight and obesity, respectively; corresponding ORs for obesity were 1.58 (95% CI 1.30–1.91) and 1.82 (95% CI 1.46–2.28). The effects of GDM and HDP were attenuated after adjusting for maternal BMI, suggesting mediation through maternal adiposity. In continuous analyses, maternal overweight and obesity were associated with increases of 0.62 (SE 0.10) and 1.26 (SE 0.13) in offspring BMI z-scores, respectively (both p < 0.001). Maternal pre-pregnancy adiposity emerged as the strongest and most consistent predictor of early-childhood adiposity in this cohort. Integrating preconception weight management and structured gestational weight gain monitoring into maternal health services may help prevent early-onset overweight and break the intergenerational cycle of obesity.