Q: What is folic acid and what does it do?

A: Folic acid is a B vitamin. When taken before and early in pregnancy it helps prevent birth defects of nervous tissue, the brain and spinal cord. Some studies show it can also prevent miscarriage, stroke, autism, and certain cancers.

Folic acid is available as a supplement, in most multivitamins, in some foods. Every fertile woman should take a multivitamin with 400 micrograms of folic acid every day before pregnancy and during early pregnancy, and 4000 micrograms if you have already had a pregnancy affected by a birth defect of the brain or spinal cord or if you had a child with autism spectrum disorder (ASD).