Maternal folic acid supplementation during pregnancy in association with childhood overweight or obesity

Objective: This study aimed to examine associations of maternal folic acid supplementation (FAS) during pregnancy with childhood overweight or obesity (OWO) or adiposity. Methods: In a population-based cohort of 1479 children, maternal FAS during pregnancy was assessed retrospectively by questionnaires. BMI and body fat percentages were measured at a mean age of 6.4 years. Pertinent factors were accounted for in data analyses. Results: Maternal FAS during pregnancy was negatively associated with OWO (adjusted odds ratio: 0.70; 95% CI: 0.50 to 0.99). There were inverse associations of maternal FAS during pregnancy with BMI z score (β: −0.22; 95% CI: −0.39 to −0.05), whole body fat percentage (β: −1.28; 95% CI: −2.27 to −0.30), trunk fat percentage (β: −1.41; 95% CI: −2.78 to −0.04), and limb fat percentage (β: −1.31; 95% CI: −2.32 to −0.30). Stratified analyses found inverse associations of FAS during pregnancy with OWO, BMI z score, and body fat percentages predominantly among children without breastfeeding and whose parents had a below-tertiary educational level. Conclusions: This study provides novel evidence that maternal FAS during pregnancy was significantly associated with a decreased risk of childhood OWO and adiposity, particularly among children with no breastfeeding and lower parental educational level.