With fast food restaurants and busy lifestyles, most people do not eat a balanced diet. It is important for all pregnant women to get adequate amounts of certain vitamins and minerals. One of these vitamins is folic acid. It helps to prevent birth defects including neural tube defects such as spina bifida. Many OB/GYNs will prescribe prenatal vitamins to women trying to conceive because recent studies have shown that women getting adequate amounts of folic acid before conception can reduce the risk of neural tube defects by 50 percent. Prenatal vitamins have the greater amounts of folic acid than any multivitamin. Also, many women become anemic during pregnancy. Most prescription prenatal vitamins contain larger amounts of iron than vitamins found over the counter.