Maternal obesity linked to childhood epilepsy and intellectual disability risks

A large South Korean study has found that mothers who carry excess weight before becoming pregnant are more likely to have children who develop epilepsy and intellectual disability, even when researchers account for a wide range of other medical factors. The finding emerges from analysis of nearly 780,000 infants born in South Korea whose mothers had documented weight measurements and completed required health screenings. The work, published in the International Journal of Obesity, suggests that the timing of weight matters—the period before conception appears to shape neurological risk in ways that persist through childhood.

The research team examined five categories of maternal body mass index, using classifications designed for Asian populations, which recognize that obesity-related health risks can emerge at lower BMI thresholds in Asian groups than in Western populations. They tracked children from birth through age five, recording diagnoses of epilepsy, intellectual disability, autism spectrum disorder, cerebral palsy, and attention deficit hyperactivity disorder. The investigators then calculated how often each condition appeared in children whose mothers fell into different weight categories, adjusting their analysis to account for maternal health conditions like diabetes and depression, as well as neonatal factors such as birth weight, delivery method, and whether infants required intensive care.

The results showed a clear pattern for two conditions. Children born to mothers with elevated pre-pregnancy BMI faced increased risks of both epilepsy and intellectual disability. The risk increase was modest but consistent: hazard ratios ranged from 1.08 to 1.37 across overweight and obese categories, meaning children in these groups were roughly 8 to 37 percent more likely to receive these diagnoses by age five compared to children born to mothers in the normal weight range. Notably, these associations held even after the researchers adjusted for all the maternal and neonatal characteristics they measured. Maternal underweight showed no significant association with neurodevelopmental disorders in the fully adjusted analysis.

Interestingly, initial unadjusted analyses had suggested links between maternal obesity and autism spectrum disorder and ADHD as well. But when the researchers accounted for maternal conditions and neonatal complications, those associations disappeared. This pattern suggests that perinatal factors—complications during pregnancy and birth—may explain some of the apparent connection between maternal weight and these particular disorders. The persistence of epilepsy and intellectual disability risks even after full adjustment indicates that maternal obesity may influence fetal brain development through pathways that operate independently of the complications typically captured in medical records: metabolic changes, inflammatory responses, hormonal shifts, or epigenetic modifications that alter how genes are expressed.

The study drew on the Korean National Health Information Database, a comprehensive resource linking maternal health screenings with infant and child health records through family identification systems. Mothers with higher pre-pregnancy BMI were more likely to be older, to have depression, gestational diabetes, and hypertension. Their infants were more likely to be born early, delivered by cesarean section, admitted to neonatal intensive care, or require resuscitation at birth. They also tended to have higher birth weights. These differences in pregnancy and birth outcomes are themselves important—they suggest that maternal obesity creates a cascade of perinatal complications that may contribute to some neurodevelopmental risks.

The work carries limitations worth noting. Maternal weight was measured up to three years before pregnancy, not at conception itself, and the study lacked information on how much weight women gained during pregnancy, which is itself a factor in fetal development. The researchers also did not have data on maternal smoking, diet, or socioeconomic status. The five-year follow-up period means that conditions emerging later in childhood—some forms of autism or learning disabilities that become apparent in school—would not have been captured. Some of the neonatal variables the researchers adjusted for, like birth weight, may themselves be consequences of maternal obesity rather than independent factors, potentially masking the true strength of the association.

Yet the study's strengths are substantial. The sample size of 779,091 infants provides statistical power to detect modest effects. The nationwide scope and integration of health screening data across the population reduce the risk of selection bias. The comprehensive adjustment for maternal and neonatal characteristics represents a rigorous attempt to isolate the independent contribution of pre-pregnancy weight. The findings align with emerging research suggesting that maternal metabolic and inflammatory states during pregnancy shape fetal brain development in ways that influence neurological function years later. The work underscores a simple but consequential message: the health decisions women make before conception—including weight management—may influence their children's neurological development in measurable ways.