A large-scale study from South Korea, published in the journal BMC Medicine in 2023, found that maternal body mass index (BMI) before pregnancy is associated with neurodevelopmental delays in toddlers. The research analyzed data from over 3 million children born between 2008 and 2015, using records from the National Health Insurance Service.
The study categorized mothers by pre-pregnancy BMI: underweight (BMI < 18.5), normal weight (18.5β22.9), overweight (23β24.9), and obese (β₯ 25). Results showed that children of underweight mothers had a 10% higher risk of developmental delays in language and cognition by age 3. Children of obese mothers faced a 20% higher risk, with the strongest links to motor and social development.
Notably, the study suggested that even overweight mothers (BMI 23β24.9) had a slightly elevated risk for cognitive delays, though the effect was smaller than for obesity. The researchers adjusted for factors like maternal age, education, and gestational diabetes, but noted that the observational design cannot prove causation.
Experts emphasize that the findings highlight the importance of pre-conception health. Dr. Kim, a lead author, stated: 'Optimizing weight before pregnancy may be a modifiable factor to support early childhood development.' However, they caution against extreme dieting, as underweight also carried risks.
