Folic Acid Supplementation Guidelines

Standard Dosing Recommendations

The American College of Physicians recommends that all women of childbearing age take a daily supplement containing 0.4 to 0.8 mg (400 to 800 μg) of folic acid to prevent neural tube defects 1, 2
Folic acid supplementation should begin at least 1 month before conception and continue through the first 2-3 months of pregnancy for maximal neural tube defect prevention 3
For women not planning pregnancy, supplementation is still recommended since approximately 50% of pregnancies in the United States are unplanned 4
After 12 weeks of gestation, continuation of 0.4 mg (400 μg) folic acid as a standard component of prenatal vitamins is recommended throughout the remainder of pregnancy to meet fetal growth and developmental needs 4

Women at high risk for neural tube defects, including those with a personal or family history of neural tube defects, require a higher dose of 4 mg (4000 μg) daily 5
High-risk criteria also include use of certain antiseizure medications, such as valproic acid and carbamazepine 6, 3
This higher dose should begin at least 3 months before conception and continue until 12 weeks gestation 4

The Upper Limit (UL) for folic acid supplementation is established at 1 mg/day (1000 μg/day) for adults, based on the risk of masking vitamin B12 deficiency 7
Even with adequate folate supplementation, not all cases of neural tube defects can be prevented due to their multifactorial etiology 4