Folic acid, also known as vitamin B9, is a water-soluble vitamin, so called because it was originally obtained from spinach leaves. Folic acid is a key player in placenta formation, normal development, and intellectual health. Deficiency of folic acid can cause megaloblastic anemia as well as leukopenia, which is especially important for mothers-to-be. Folic acid is actually an essential cofactor in the body’s metabolic process. One of the metabolisms it dominates is called homocysteine metabolism. And what is homocysteine (Hcy)? Homocysteine is an intermediate product of methionine metabolism. Of course, one just has to remember that if the Hcy in the blood is high, it is easy to develop diseases such as placental abruption, pre-eclampsia, and more likely to induce recurrent miscarriage. So what causes poor folic acid utilization? Folic acid metabolism requires several enzymes. The first is 5,10-methylenetetrahydrofolate reductase (or MTHFR), located at position lp36.3 on chromosome 1. If there is a problem with this enzyme, it can directly or indirectly lead to neural tube defects in newborns or fetuses as well as cancer and cardiovascular disease in adults. The second one is methionine synthase reductase (MTRR), located at 5p15.3-p15.2. If there is a problem with MTRR, folate metabolism will also be impaired, which is closely related to spina bifida, neural tube defects, leukemia and other diseases. If we detect abnormalities in the relevant genes, we need to evaluate the degree of risk. For people with mild utilization disorders, 400 mcg/day of folic acid is needed in the first 3 months of pregnancy and in the early stages of pregnancy (before 0~12 weeks). In mid/late pregnancy (13-40 weeks), food supplementation is indicated and no additional supplementation is required. For those with moderate utilization disorders, folic acid supplementation of 400 mcg/day is required during the first 3 months of pregnancy and 800 mcg/day during early pregnancy (before 0-12 weeks). For mid/late pregnancy (13-40 weeks) 400 mcg/day. For people with severe utilization disorders, 800 mcg/day of folic acid is required in the first 3 months of pregnancy and in the early stages of pregnancy (before 0-12 weeks). 400 mcg/day in mid/late pregnancy (13-40 weeks). It is important to note that the above supplemental doses refer to the intake of synthetic folic acid supplements or fortification and do not include food. In addition, excessive intake of folic acid can interfere with the absorption of zinc. For all adults, including pregnant women and lactating mothers, the tolerable maximum intake (UL) of synthetic folic acid preparations is 1000 mcg/day. It’s true that the more you take of anything, the better. So how can you tell if you are in the mild, moderate, or severe folic acid utilization disorder group? Of course, we need to do a test first, i.e. a genetic testing program for folic acid utilization ability. So who needs to do these programs? Women who have had unexplained miscarriages, premature births, deformed babies or even stillbirths; 3. Women who have had preconception/early pregnancy (0-12 weeks) to prevent the occurrence of neural tube abnormalities; 4. Women who have had mid-pregnancy (13-27 weeks) to prevent the occurrence of hyperemesis and late-onset miscarriages; 5. Women who have had preconception/early pregnancy (0-27 weeks) to prevent the occurrence of megaloblastic anemia; 6. Women with elevated plasma homocysteine (Hcy>10umol/L); 7. Women with a family history of congenital heart disease; 8. Women with hypertension during pregnancy, a genetic history of hypertension, and women at risk for Down syndrome.