MTHFR gene test TT, means that the folic acid metabolizing enzyme in the body of the tested person is severely deficient and is not able to absorb, metabolize and utilize folic acid normally. MTHFR gene test, which is the folic acid metabolizing gene test, the test result is divided into three types: CC type, CT type and TT type, among which CC type is normal, CT type is basically normal and TT type is abnormal. If a woman in the preparation period or early pregnancy has MTHFR gene test TT type, it indicates that the patient has impaired absorption, metabolism and utilization of folic acid and is prone to folic acid deficiency in the body. The baby is prone to congenital heart disease, neural tube development malformations such as hydrocephalus, anencephaly and cleft lip and palate after pregnancy. Pregnant women are also prone to diseases such as gestational hypertension and megaloblastic anemia during pregnancy, which require active folic acid supplementation to prevent adverse consequences.