As a vitamin, folic acid is important for generating blood cells and promoting normal nerve development. If a pregnant woman is deficient in folic acid in the early stages of pregnancy, it can easily lead to congenital malformations in the fetus. Among them, neural tube development disorder is the most common, which mainly affects the normal development of the brain and spinal cord. For example, the familiar spina bifida is a common malformation. Other common malformations include cleft lip, cleft palate, cardiac and genitourinary malformations. The “China-US Neural Tube Malformation Prevention Cooperation Program”, in 30 cities and counties in Hebei, Shanxi, Jiangsu and Zhejiang provinces, through nearly 250,000 cases of women of childbearing age, folic acid levels have been tested, and finally proved with a large sample of data: women of childbearing age, before and after pregnancy, the daily supplementation of 0.4mg of folic acid in small doses supplements can indeed be effectively reduce the incidence of birth defects, especially neural tube malformations. Therefore, women who plan to become pregnant should take folic acid supplements in advance, usually three months in advance. If you take folic acid supplements when you realize you are already pregnant, it will probably be too late. For women with epilepsy, the dose of folic acid supplementation may have to be larger than for normal women, especially if they are taking phenytoin sodium, carbamazepine, or stupid barbiturates, as these medications can interfere with the absorption of folic acid. Increased folic acid supplementation is also recommended for patients taking multiple antiepileptic drugs or taking greater than 1,000 mg of valproic acid per day. If there have been cases of neural tube malformations in previous births, the dose of folic acid supplementation should also be increased accordingly, usually by starting folic acid tablets 3 months prior to pregnancy until 3 months after pregnancy, for a total duration of 6 months. For patients taking both phenytoin sodium and larger doses of folic acid, the blood concentration of phenytoin sodium should be checked regularly, as large doses of folic acid have the potential to lower the concentration of phenytoin sodium, which in turn can lead to exacerbation of seizures. Therefore, female epileptic patients should visit the hospital on time and adjust the dosage of antiepileptic drugs and folic acid in time according to their conditions.