Differential Impacts of Prenatal Supplement Intake on Childhood Obesity Markers, Stratified by Gender and Other Prenatal Factors.

Objective: To assess the association between maternal iron, folic acid and combined iron-folic acid (IFA) oral supplementation during pregnancy and childhood obesity markers in 9- to 13-year-olds. Methods: Data from the 2007-2009 Healthy Growth Study were analysed. The study assessed obesity markers, i.e., body mass index (BMI), skinfold thickness and waist circumference. The research question was examined using generalised linear models stratified by the child's sex, maternal prepregnancy weight and gestational age. Results: Folic acid and IFA supplements, but not iron alone, were significantly associated with lower waist circumference in all children (coef. -1.35, 95% CI: -2.47 to -0.23; coef. -1.01, 95% CI: -2.21 to -0.23, p < 0.05). These associations were observed only in girls with lower BMI (coef. -0.88), skinfold thickness (coef. -4.92) and waist circumference (coef. -2.99) with folic acid and similar IFA effects. Interestingly, in boys born to obese mothers before pregnancy, a significant negative association was observed for folic acid alone with BMI (coef. -3.55) and waist circumference (coef. -7.09) and IFA for the sum of skinfold thickness (coef. -19.68). Conclusion: Maternal folic acid and IFA supplementation may contribute to a lower likelihood of childhood obesity, especially in girls and children of underweight or obese mothers, emphasising the importance of proper prenatal nutrition.