Folic acid is required after pregnancy and folic acid needs to be taken orally until the third trimester of pregnancy. Folic acid is involved in the synthesis of DNA and RNA, and folic acid deficiency predisposes the fetus to neural tube defects, miscarriage, preterm birth, and low birth weight. The Centers for Disease Control and Prevention recommends that all women before and after pregnancy should take 0.4 mg of folic acid daily to prevent more than 50% of fetal neural tube defects. Pregnant women in China also need additional folic acid supplementation in their normal balanced diet, before or after pregnancy if possible. For pregnant women who cannot have a normal balanced diet, it is not easy to control the dose of a single vitamin or mineral and it is cumbersome to take it.