Association between Maternal Pre-Pregnancy BMI and Early Motor Development in Chinese Infants: A Prospective Birth...

Maternal weight management during pregnancy is important for infant health, given the potential impact of overweight on offspring neurodevelopment. This study aimed to examine the association between maternal pre-pregnancy body mass index (BMI) and infant motor development delay during the first year of life.

This prospective cohort study included 227 mother-child pairs. Maternal pre-pregnancy BMI, calculated as weight (kg)/height (m)², was analyzed as both a continuous and a categorical variable (underweight: <18.5 kg/m²; normal: 18.5-23.9 kg/m²; overweight/obese: ≥24 kg/m²). Infant motor development was assessed using the Alberta Infant Motor Scale (AIMS) at 3, 6, 9, and 12 months of age. Group differences were tested with standard univariate methods. We used linear and non-linear regression models to explore potential associations between pre-pregnancy BMI and AIMS total scores.

This study found that 26% of the mothers had pre-pregnancy overweight/obesity. Among the infants, 115 were boys, and 112 were girls, and the mean birth weight was 2.61 ± 0.50 kg. After full adjustment, higher pre-pregnancy BMI was inversely associated with 12-month AIMS total scores (β = - 0.37, 95% CI: -0.69 to -0.05). A significant J-shaped non-linear association was identified, with BMI ≥25 kg/m² marking a threshold for elevated motor delay risk. For BMI ≥25 kg/m², each 1-kg/m² increase corresponded to a 1.22-point reduction in AIMS total scores and a 96% higher odds of atypical motor development (OR = 1.96, 95% CI: 1.28-3.00).

Elevated maternal pre-pregnancy BMI is associated with increasing motor delay during infancy, with a non-linear threshold near BMI ≥25 kg/m². Preconception weight management is vital for optimizing early neurodevelopment.

· Maternal pre-pregnancy overweight/obesity may influence infant neurodevelopment.. · Elevated pre-pregnancy BMI (≥25 kg/m2) significantly increases the risk of atypical motor development.. · Preconception weight management may help optimize early motor development outcomes..