A: Folic acid (also called folate or folacin) is a naturally occurring B vitamin found in green leafy vegetables and other foods. It's essential for normal brain and spinal cord development. When taken before and during early pregnancy, it works to prevent neural tube defects, a devastating condition that affects one to two pregnancies per 1,000. It's hard to get enough of this important vitamin through diet alone, which is why supplementation is recommended.

Some 25,000 babies are born each year in the United States with neural tube defects, including spina bifida and anencephaly. The March of Dimes estimates that this number could decrease by 70 percent if all women had adequate folic acid during early pregnancy.

For the healthiest start to your pregnancy, take 400 micrograms of folate when trying to conceive and continue this during your pregnancy. If you have had a prior pregnancy complicated by a neural tube defect, or have a close family member who had a condition caused by neural tube defects, you should increase your intake to 5 milligrams of folic acid daily. Good dietary sources of folic acid include spinach, asparagus, broccoli, Romaine lettuce, lentils, black beans, peanuts, orange juice, fortified bread, pasta and cereals.