Maternal obesity raises childhood epilepsy and disability risks, new study shows

By Priyanjana Pramanik, MSc.Reviewed by Susha Cheriyedath, M.Sc.Nov 17 2025

A national Korean cohort study reveals that elevated pre-pregnancy BMI independently increases childhood risks of epilepsy and intellectual disability, underscoring the importance of maternal health long before conception.

Study: Maternal pre-pregnancy body mass index and the risk of neurodevelopmental disorders in offspring. Image Credit: pecky_photograph / Shutterstock

In a recent International Journal of Obesity study, researchers examined the relationship between maternal body mass index before pregnancy and the risk of neurodevelopmental disorders in children.

Their findings indicate statistically significant associations between maternal obesity and higher risks of offspring developing intellectual disability and epilepsy in a South Korean population, but not between maternal underweight and adverse neurodevelopmental outcomes in the fully adjusted model.

Rising Obesity Trends Among Reproductive-Age Women

Obesity rates among women of reproductive age are rising globally, including in Asia. Although obesity has historically been more prevalent in Western countries, recent data from Korea and neighboring regions show increasing rates among young and middle-aged women.

In Korea, these rising trends raise concerns for maternal and child health. The World Health Organization recommends Asia-Pacific BMI categories because Asian populations may experience obesity-related risks at lower BMI levels.

Maternal Obesity and Potential Neurodevelopmental Effects

A growing body of research has investigated how maternal obesity may affect offspring's health beyond metabolic disorders. It is well established that children of mothers with overweight or obesity are more likely to develop obesity themselves.

Emerging work suggests that elevated maternal BMI may also influence early neurobehavior, brain development, and later mental health. 

Prior studies have identified potential links between maternal obesity and poorer neonatal cognitive outcomes, altered neural connectivity, and increased risks of subsequent neurodevelopmental difficulties.

Study Objective and Data Source Selection

Researchers assessed whether maternal pre-pregnancy BMI is associated with neurodevelopmental disorders such as attention deficit hyperactivity disorder, autism spectrum disorder, intellectual disability, cerebral palsy, and epilepsy. These risk assessments used BMI classifications modified for Asian populations.

The team analyzed data from the Korean National Health Information Database, a comprehensive nationwide resource that integrates healthcare utilization, insurance claims, and routine health screenings. 

Maternal information was sourced from an adult screening program, while infant and child data were drawn from corresponding screening programs. Mother-infant pairs were linked using the family tree database based on insurance and resident registration data.

Maternal BMI Categories and Covariate Definitions

Maternal BMI measured within three years before delivery was classified using Asia-Pacific categories that define underweight, normal weight, overweight, obese class I, and obese class II.

Maternal conditions, including hypertension, diabetes, gestational diabetes, and depression, were identified. Neonatal variables included gestational age, preterm birth status, birth weight, small for gestational age classification, congenital anomalies, neonatal intensive care unit admission, delivery mode, and resuscitation procedures.

Neurodevelopmental diagnoses were identified from birth to age five. Incidence rates were calculated per one thousand person-years. Hazard ratios across BMI groups were estimated using Cox proportional hazards models adjusted for maternal and neonatal confounders.

Maternal and Neonatal Characteristics by BMI Group

The study assessed 2.28 million live births in South Korea, ultimately including 779,091 infants whose mothers had BMI data and who completed required health screenings. Mothers were assigned to five BMI categories, with the majority falling within the normal range.

Higher maternal BMI was strongly associated with older age, depression, gestational diabetes, and chronic and pregnancy-related hypertension. Neonatal characteristics also varied by maternal BMI. 

Infants of women with higher BMI were more likely to be born preterm, delivered by cesarean section, admitted to the neonatal intensive care unit, or require resuscitation. These infants had higher birth weights and were less likely to be small for gestational age.

Associations Between Maternal BMI and Neurodevelopmental Disorders

In unadjusted analyses, severe maternal obesity was associated with elevated risks of autism spectrum disorder, intellectual disability, cerebral palsy, and epilepsy. After adjustment for neonatal factors, overweight and class I obesity remained significantly associated with increased risks of epilepsy and intellectual disability, while class II obesity was linked to higher risks of autism spectrum disorder and attention deficit hyperactivity disorder in a clearer dose-response pattern.

In the fully adjusted model that accounted for maternal and neonatal characteristics, the associations with autism spectrum disorder and attention deficit hyperactivity disorder were no longer significant. However, increased risks of epilepsy and intellectual disability persisted, with hazard ratios ranging from approximately 1.08 to 1.37 across BMI groups.

Maternal underweight was not associated with neurodevelopmental disorders in the fully adjusted model, although a small association with epilepsy was seen in the neonatal-adjusted model.

Interpretation of Residual Risks After Full Adjustment

This extensive population-based study found that higher maternal pre-pregnancy BMI is independently associated with modest-to-moderate increases in the risk of epilepsy and intellectual disability in offspring, even after extensive adjustment for confounders.

The findings align with earlier research suggesting that maternal obesity may influence fetal neurodevelopment through metabolic, inflammatory, hormonal, or epigenetic pathways. 

Although initial models identified associations with cerebral palsy, autism spectrum disorder, and attention deficit hyperactivity disorder, these did not persist after full adjustment, indicating that perinatal or maternal factors captured in the models may account for part of the observed associations.

Methodological Strengths and Study Limitations

Key limitations include reliance on BMI measured up to three years before pregnancy, absence of gestational weight gain and socioeconomic data, and lack of information on maternal smoking and dietary patterns.

The five-year follow-up period limits the assessment of later-emerging neurodevelopmental disorders. Some neonatal variables may function as intermediates, possibly attenuating true associations. 

Strengths include the very large sample size, nationwide data coverage, and comprehensive adjustment for maternal and neonatal characteristics. Overall, the study highlights the importance of preconception weight management in supporting long-term neurodevelopmental health in children.