The reason for taking folic acid before or after pregnancy is that folic acid is involved in the entire process of human metabolism. Folic acid deficiency can lead to the development of fetal neural tube malformations and can also increase the chances of malformations in the major organs of the fetus, so it is recommended to start taking oral folic acid from 3 months before pregnancy. It is emphasized to start taking folic acid before pregnancy because it is necessary to maintain the folic acid in the woman’s body at a certain level, which can effectively prevent some of the fetal malformations. It takes 4 weeks for the folic acid deficiency in a woman’s body to be corrected after taking folic acid. Therefore, in early pregnancy, the sensitive period for the formation of fetal neural tube malformations, there is enough folic acid to meet the needs of the development of the nervous system. However, folic acid obtained from food alone cannot meet the body’s needs, so women are advised to take a daily supplement of 0.4-0.8mg of folic acid before pregnancy in addition to eating more green leafy vegetables and fruits with the aim of reducing the incidence of fetal neural tube malformations.