Elevated Maternal Serum Folate in the Third Trimester and Reduced Fetal Growth: A Longitudinal Study

This study aimed to examine the association of fetal growth and elevated third trimester maternal serum folate due to folic acid (FA) supplement intake. Dietary intake, use of FA supplements, weight, and blood biomarkers of B-vitamins (serum folate, pyridoxal, vitamin B(12), and plasma total homocysteine) were observed in 33 healthy pregnant women at the third trimester (average gestational age 35 wk). Birth outcomes were assessed through hospital birth records. Infant anthropometry and maternal blood biomarkers were followed up at 1 mo postpartum. Fourteen women were taking FA supplements at the third trimester. Dietary intake was similar among FA users and non-users, but serum folate and pyridoxal were significantly higher in users (11.6±6.7 vs. 6.1±3.2 ng/mL, and 13.8±21.7 vs. 3.2±1.4 ng/mL, respectively). Plasma total homocystein (tHcy) was higher in non-users compared to users, but not significantly. Nine FA users and eight non-users had low serum vitamin B(12) values (