Folic acid is a B vitamin, chemically known as “pteroyl monoglutamic acid”, which was first isolated from spinach in the 1940s, hence its name. The human body cannot synthesize folic acid and must rely on exogenous supplies. Fresh green leafy vegetables, soy products, yeast bread, strawberries and orange fruits, animal liver, and beef are all rich in folic acid. American nutritionists recommend pregnant women to eat one banana a day, which is rich in folic acid, vitamin B6 and trace elements such as potassium and magnesium and crude fiber, which are beneficial to maternal health. If a woman’s usual diet is deficient in folic acid, even if she takes folic acid tablets as a supplement immediately, it takes 4-8 weeks for the folic acid deficiency in her body to be corrected. This is the critical time for the development of the fetal neural tube. Therefore, if a mother-to-be waits until she is pregnant to take folic acid tablets, she will also miss the best time to prevent neural tube abnormalities. According to statistics, 80% of couples in China become pregnant within one year of marriage, so women who have no plans to have children in the near future should start taking folic acid after marriage, unless they are using contraception. Folic acid is also a vitamin that prevents Down’s syndrome, congenital heart and digestive tract malformations, and low birth weight babies. A small dose of 0.4 mg of folic acid per day is appropriate for the prevention of birth defects and can be taken until the first 3 months of pregnancy. Folic acid tablets taken during pregnancy preparation are over-the-counter and can be bought directly from pharmacies. After the third month of pregnancy, the fetus’ demand for vitamins will increase, at which time you can replace the folic acid tablets with a multivitamin for pregnant women. Pregnant women at high risk, such as those with impaired folate metabolism, a history of multiple miscarriages, a history of delivery of fetuses with neural tube abnormalities, and a family history of high incidence of neural tube abnormalities, may increase the dose to 0.8 mg per day, but it is not recommended to exceed 1.0 mg per day, as continuing to increase folic acid intake does not further reduce the incidence of neural tube abnormalities. Excessive doses of folic acid supplements do have some side effects, such as affecting the body’s absorption of zinc, and zinc deficiency can also lead to intrauterine growth retardation, low birth weight, gestational blood pressure, and stalled labor. In addition, high dose folic acid intake can mask the symptoms of vitamin B12 deficiency affecting hematopoiesis, thus hindering the diagnosis of pernicious anemia and allowing the neurological damage caused by pernicious anemia to continue to progress. Some studies have also found that particularly high doses of folic acid can cause epilepsy. A Norwegian study showed that women with high plasma folate levels during pregnancy had an increased risk of developing asthma in their children by age 3. Women who take high doses of folic acid later in pregnancy may have an increased risk of breast cancer. However, these case study subjects were all on high doses of folic acid for a long time, such as the treatment of anemia dose of 5 mg daily orally, whereas no correlation was found with the above in small doses of folic acid such as the recommended dose of 0.4 mg daily after preconception. Therefore, it is important not to confuse the two dose forms of folic acid for the treatment of anemia (5mg/tablet) and the low dose folic acid for the prevention of birth defects (0.4mg/tablet). Because of the significance of folic acid supplementation before and after pregnancy for the prevention of birth defects, and because the results of studies related to the risks associated with the administration of folic acid are not clear, WHO at all levels continues to recommend low-dose folic acid supplementation before and after pregnancy. Newlyweds are currently given three free bottles of folic acid distributed by the state at the time of marriage registration.