Folic acid supplementation should begin in the first trimester and continue until 12 weeks of gestation in normal pregnant women. Folic acid supplementation can be discontinued after completion of NT and early Down’s syndrome screening tests for elimination screening at 11-13 weeks of gestation. Folic acid is effective in preventing fetal neural tube abnormalities. In addition to consuming more folic acid-rich foods such as fresh green leafy vegetables in the daily diet structure, basic supplementation is recommended for pregnancy preparation. The regulation of folic acid intake has been enriched by the development of the MTHFR gene test for folic acid metabolic capacity. For example, MTHFR gene test type CC is high enzyme activity, supplementation of 0.4mg/day before and early pregnancy and discontinuation in mid and late pregnancy; type CT is medium enzyme activity, supplementation of 0.8mg/day in early pregnancy and 0.4mg/day in pre and mid and late pregnancy; type TT is low enzyme activity, supplementation of 0.8mg/day in pre and early pregnancy and 0.4mg/day in mid and late pregnancy. It is recommended that women preparing for pregnancy should undergo a genetic test for folic acid metabolism ability MTHFR and adjust the intake of folic acid according to the genetic test results.