Do Adverse Intrauterine Environments Affect Body Mass Index in Infants and Preschool Children?

INTRODUCTION: Exposure to adverse intrauterine environments resulting from different maternal clinical conditions may alter childhood growth patterns. This study investigated the influence of such environments on body mass index-for-age (BMI-for-age) trajectories from birth to preschool age. METHODS: A total of 342 mother-child dyads recruited from three hospitals in southern Brazil were allocated into five groups: diabetes mellitus (DM), systemic arterial hypertension (SAH), maternal smoking, small for gestational age (SGA, used here as a proxy for impaired fetal growth), and a control group. Children were assessed at seven time points from birth to preschool age using anthropometric measurements to calculate BMI-for-age z-scores. RESULTS: Generalized estimating equations (GEE) identified a significant interaction between group and time (p < 0.001). Among girls, at birth, the DM group presented higher BMI-for-age z-scores than the smoking group and reached elevated BMI-for-age z-scores at preschool age, differing from the control group. At 6 months of age, girls in the SGA group showed a marked increase in BMI-for-age. Among boys, the SGA group reached higher BMI-for-age values at preschool age than the DM and control groups. Differences were observed across time, group, and sex in the SGA and control groups (p < 0.001). CONCLUSION: These findings suggest that adverse intrauterine environments may influence BMI-for-age trajectories during early life, with greater variability and evidence of catch-up growth among children exposed to maternal DM and SGA. Results should be interpreted cautiously due to unequal subgroup sizes and substantial loss to follow-up at preschool age.