Natural Folate vs. Synthetic Folic Acid in Pregnancy

In this two-arm, double-blind randomized pilot study, the investigators will recruit 60 generally healthy, low-risk pregnant women aged 19-42 years living in Vancouver, Canada. Participants will be randomized to supplement with either 0.6 mg/day folic acid or an equimolar dose (0.625 mg/day) of (6S)-5-methyltetrahydrofolic acid for 16-weeks of their pregnancy. Randomization will occur at 8-21 weeks gestation (after neural tube closure) to reduce the risk of harm should the natural folate prove less effective. All participants will also receive a prenatal multivitamin not containing any form of folate, to ensure adequacy of other nutrients (e.g. iron) required during pregnancy. Three-hour fasting venous blood samples will be collected at baseline and endline to measure serum and red blood cell folate, unmetabolized folic acid and other related biomarkers. Women will be given the option to continue supplementing until 1-week postpartum, and provide a small (3mL) breastmilk sample in order to measure differences in folates in breastmilk. These pilot data will be used to inform a definitive trial regarding the most effective form of folate supplementation for mothers and their babies.