Folic acid is a naturally occurring B vitamin that helps a baby's neural tube - the part of a developing baby that becomes the brain and spinal cord - develop properly. It must be taken before and during early pregnancy when the neural tube is developing. The best way to get enough folic acid is to take a multivitamin with 400 micrograms of folic acid in it and eat a healthy diet. Most multivitamins have this amount, but check the label to be sure. You also can get folic acid in your diet, but it's hard to get enough every day through food alone. That's why the March of Dimes encourages all women of childbearing age to take a multivitamin containing folic acid every day as part of a healthy diet. Folic acid works, but it only works if taken before and during the first few weeks of pregnancy, when the neural tube is developing into the brain and spinal cord. When the neural tube does not close properly, a baby is born with a very serious birth defect called a neural tube defect (NTD). About 3,000 pregnancies are affected by NTDs each year in the United States. If all women took adequate folic acid before conception and during pregnancy, 50 to 70 percent of NTDs could be prevented. Folic acid has no known toxic level. If you ate a bowl of fully fortified cereal (400 micrograms), took a folic acid supplement (400 micrograms), and ate fortified foods and foods rich in folate, you would not get too much folic acid. Still, the U.S. Centers for Disease Control and Prevention recommends that women consume no more than 1,000 micrograms of synthetic folic acid a day。