Children born to mothers with excess body weight have increased risk of cognitive and behavioral impairments. These effects may be mediated by effects on child brain structure and function. We used longitudinal data from a large neuroimaging cohort beginning in infancy to test the hypothesis that excess maternal weight negatively influences myelin development and general cognitive development over the first 5 years of life.
Longitudinal datasets quantifying myelin water fraction (MWF) via mcDESPOT were derived from MRI scans conducted in 204 neurotypical children stratified by reported maternal pre-pregnancy BMI (46 with obese, 62 with overweight and 96 with normal weight mothers). Mullen Early Learning Composite scores (ELS) were obtained within 7 days of MRI. Children under 2.5 years of age were assessed at 6 month intervals, while older children were assessed yearly. Each child was assessed at least once, with some having up to 6 follow-up visits. Groups were matched for relevant factors including gestational age, birth weight, gender, ethnicity, maternal education and infant feeding method.
Group differences in myelin growth curves were apparent such that children with obese or overweight mothers showed slower myelination rates and lower peak myelin values in corpus callosum and frontal cortex than those of normal-weight mothers. ELS values were lowest overall in children with obese mothers, and showed a linear decrease with age in children of obese and overweight mothers, compared to an increase with age among those with normal-weight mothers.
Maternal obesity may impact cognitive and behavioral development in children by slowing myelination within brain regions subserving cognition. Future analyses in this cohort will explore the influence of additional early life obesity risk factors on multiple metrics of brain development.