For pregnant women, there are currently two main dosage forms for preventive medication: 0.4mg and 5mg. The 0.4mg low-dose folic acid is a supplement used as a preventive measure. Pregnant women can take low-dose folic acid to prevent neural tube defects in the fetus. The recommended usage is to start taking it three months before planning pregnancy and continue until the third month of pregnancy, with a daily intake of 0.4 - 0.8mg of folic acid or folic acid-containing multivitamins. Women who have previously given birth to a child with a neural tube defect (NTD) need to take 4mg of folic acid daily. For preventive medication during pregnancy, the recommended daily dosage is 0.4mg. The 5mg dosage is a high dose, equivalent to 12.5 times the 0.4mg dosage, primarily used to treat anemia. The adult dosage is oral administration three times a day, 1 - 2 tablets each time. The pediatric dosage is oral administration three times a day, one tablet each time. Pregnant women should avoid taking high-dose folic acid tablets in the early stages of pregnancy, as long-term high doses can have adverse effects on both the mother and the fetus. Medication should always be taken under the guidance of a physician.