Prevention of birth defects with folic acid (folate)
Experts recommend taking 400 micrograms (mcg) of folic acid every day before you get pregnant through the first 3 months of pregnancy. If you are thinking about getting pregnant in the near future, you should take a multivitamin that contains 400mcg of folic acid.
Women who have had a baby with a neural tube defect will need a higher dose of folic acid. If you have had a baby with a neural tube defect, you should take 400 micrograms 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 and 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.
Johnson TRB, Gregory KD, Niebyl JR. Preconception and prenatal care: Part of the continuum. In: Gabbe SG, Niebyl JR, Simpson JL, eds. Obstetrics: Normal and Problem Pregnancies. 5th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2007:chap 5.
Neural tube defects. ACOG Practice Bulletin No. 44. American College of Obstetricians and Gynecologists. Obstet Gynecol. 2003;102:203–213.
Cunningham FG, Leveno KJ, Bloom SL, et al. Preconceptional counseling. In: Cunnigham FG, Leveno KL, Bloom SL, et al, eds. Williams Obstetrics. 23rd ed. New York, NY: McGraw-Hill; 2010:chap 7.