Ask the Experts
Folic acid: how much and when?
I’d like to get pregnant soon. Should I be taking folic acid now?
Absolutely. Experts agree that this B vitamin reduces the risk of neural-tube defects (NTDs), such as spina bifida, and new research suggests it may also reduce the risk of cleft lip and cleft palate. Where they differ is in how much women need. The American College of Obstetricians and Gynecologists recommends that all women who could become pregnant or are trying to conceive take 0.4 milligram (400 micrograms) daily.
The U.S. Preventive Services Task Force advises such women to take 0.4 to 0.8 milligram daily. But Nicholas Wald, the British researcher who demonstrated folic acid’s role in preventing NTDs, says that all women who are trying to conceive should take 5 milligrams daily, the amount already recommended for those with a previously affected pregnancy. He says 0.4 milligram will prevent about 40 percent to 50 percent of neural-tube defects; 5 milligrams about 80 percent. If you opt to take 5 milligrams, you will need a prescription. Trying to get that much from multivitamins could lead to potentially toxic levels of other nutrients, such as vitamin A. Wald suggests continuing the higher dose for the first two to three months of pregnancy.