From the Guidelines
The recommended dose of folic acid for women who are planning or capable of pregnancy is 0.4 to 0.8 mg (400 to 800 μg) per day, as evidenced by the USPSTF recommendation statement 1. This dose has been shown to reduce the risk of neural tube defects in the developing fetus.
- The USPSTF found convincing evidence that supplements containing 0.4 to 0.8 mg of folic acid in the periconceptional period reduce the risk for neural tube defects 1.
- Good evidence from randomized trials suggests that a multivitamin with 0.8 mg of folic acid reduces the risk for neural tube defects 1.
- Observational studies report a reduction of neural tube defects in women taking a supplement with 0.4 mg of folic acid 1. It is essential to start folic acid supplementation at least 1 month before conception and continue daily supplements through the first 2 to 3 months of pregnancy.
- Most studies indicate the need to start folic acid supplementation at least 1 month before conception and to continue daily supplements through the first 2 to 3 months of pregnancy 1. Given that 50% of pregnancies in the United States are unplanned, clinicians should advise all women who are capable of pregnancy to take folic acid supplements.
- Studies also indicate that 50% of pregnancies in the United States are unplanned, and clinicians should therefore advise all women who are capable of pregnancy to take folic acid supplements 1.
From the FDA Drug Label
Except during pregnancy and lactation, folic acid should not be given in therapeutic doses greater than 0.4 mg daily until pernicious anemia has been ruled out. The recommended dose of folic acid is not explicitly stated for all cases, but it should not exceed 0.4 mg daily in non-pregnant and non-lactating patients until pernicious anemia has been ruled out 2.
From the Research
Recommended Dose of Folic Acid
The recommended dose of folic acid varies depending on the individual's risk level and circumstances.
- For women with a low risk for a neural tube defect or other folic acid-sensitive congenital anomaly, a daily oral multivitamin supplement containing 0.4 mg folic acid is recommended for at least 2 to 3 months before conception, throughout the pregnancy, and for 4 to 6 weeks postpartum or as long as breast-feeding continues 3.
- Women with a moderate risk require a diet of folate-rich foods and daily oral supplementation with a multivitamin containing 1.0 mg folic acid, beginning at least 3 months before conception 3.
- Women with a high risk for a neural tube defect require a diet of folate-rich foods and a daily oral supplement with 4.0 mg folic acid for at least 3 months before conception and until 12 weeks' gestational age 3.
- The Belgian Superior Health Council recommends a minimum of 400 micrograms of folic acid or folate supplementation per day from 4 weeks before conception to 8 weeks thereafter 4.
- A study found that a fortification program that delivered 200 micrograms of folic acid daily to women would be effective against neural tube defects and safer for the general population 5.
- The Institute of Medicine recommends that all women of childbearing potential consume 400 microg of synthetic folic acid per day from fortified foods and/or a supplement in addition to food folate from a varied diet 6.
- The desired dietary intake of folate to prevent an increase in plasma homocysteine levels is at least 350 micrograms per day 7.
Key Considerations
- Women should be advised to maintain a healthy folate-rich diet, but folic acid/multivitamin supplementation is needed to achieve the red blood cell folate levels associated with maximal protection against neural tube defect 3.
- Folic acid supplementation is unlikely to mask vitamin B12 deficiency, and investigations are not required prior to initiating folic acid supplementation for women with a risk for primary or recurrent neural tube or other folic acid-sensitive congenital anomalies 3.