Taking folic acid before and during pregnancy can reduce the risk of certain birth defects. These include spina bifida, anencephaly, and some heart defects.
Experts recommend women who can become pregnant or who plan to become pregnant take at least 400 micrograms (µg) of folic acid every day.
This is because many pregnancies are unplanned. Also, birth defects often occur in the early days before you may know you are pregnant.
If you become pregnant, you should take a multivitamin with 600 µg of folic acid. Taking a multivitamin with folic acid helps ensure that you get all the nutrients you need during pregnancy.
Women who have had a baby with a neural tube defect may need a higher dose of folic acid. If you have had a baby with a neural tube defect, you should take 400 µg of folic acid every day, even when you are not planning to become pregnant. If you plan to become pregnant, you should talk to your doctor about whether you should increase your folic acid intake to 4 milligrams (mg) each day during the month before you become pregnant until at least the 12th week of pregnancy.
Prevention of birth defects with folic acid (folate)
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US Preventive Services Task Force. Folic acid for the prevention of neural tube defects: US Preventive Services Task Force Recommendation Statement. Ann Intern Med. 2009;150(9):626-631. PMID: 19414842 www.ncbi.nlm.nih.gov/pubmed/19414842.
West EH, Hark L, Catalano PM. Nutrition during pregnancy. In: Gabbe SG, Niebyl JR, Simpson JL, et al, eds. Obstetrics: Normal and Problem Pregnancies. 7th ed. Philadelphia, PA: Elsevier; 2017:chap 7.
Review Date 5/10/2017
Updated by: Anita Sit, MD, Department of OB/GYN, Santa Clara Valley Medical Center, San Jose, CA (for identification purposes only). Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.