Usually, folic acid is recommended to be taken until the first 3 months of pregnancy. If folic acid is not supplemented before pregnancy, it can be taken until the 6th month of pregnancy. Folic acid is a water-soluble vitamin that can be taken during pregnancy to prevent fetal neural tube abnormalities, such as anencephaly, spina bifida, and spinal bulge, and is important for normal fetal growth and development. In addition, deficiency of folic acid can cause megaloblastic anemia. In the absence of adverse maternal history and other risk factors, the recommended dosage of folic acid is 0.4 mg, starting from the first 3 months of pregnancy to the third trimester. If you have a history of adverse pregnancy and childbirth, especially neural tube abnormalities, you need to choose the appropriate dosage under the guidance of your doctor, and generally start supplementation from the first 3 months of pregnancy to the whole pregnancy. As the gestational weeks increase, the fetus needs more nutrients for growth and development than during non-pregnancy, pregnant women can also supplement folic acid by taking oral multivitamins containing folic acid.