I. What is folic acid? Folic acid is a water-soluble B vitamin that plays an important role in cell division and growth, synthesis of nucleic acids, amino acids and proteins, and is an indispensable nutrient for fetal growth and development. II. When is the best time to take folic acid? Women who are preparing for childbirth should take folic acid supplementation in advance. Women with poor folic acid metabolism during pregnancy should increase the dose of supplementation. III. What are the main functions of folic acid? 1. Prevention of fetal neural tube malformation (anencephaly, spina bifida), with an efficiency of 85%. 2. Prevention of fetal cleft lip and palate, with an efficiency of 50%. 3. Prevention of birth defects such as fetal precocious heart disease and other body surface malformations. 4. Prevent anemia in pregnant women, lactating mothers and fetuses. 5. Promote the development of fetal nervous system. 6. Reduce infant mortality. 7. Reducing pregnancy reactions, etc. IV. What is the dosage of folic acid? Folic acid metabolic capacity is determined by testing the relevant genes to determine the dosage of folic acid supplementation in the first, second and third trimesters of pregnancy, thus making the amount of folic acid supplementation more accurate. Since different malformations can appear at different times during the development of the fetus, and some malformations do not become apparent until after birth, pregnant women are expected to have regular prenatal checkups as prescribed by their doctors.