Folic acid is taken in the first trimester of pregnancy. Folic acid deficiency can cause neural tube abnormalities in the fetus, and the development of the fetal neural tube begins in the early stages of pregnancy. Starting to take folic acid in the first trimester of pregnancy will enable the pregnant woman to reach a certain level of folic acid in her body so that she can prevent the fetus from developing neural tube abnormalities. If folic acid supplements are only started after pregnancy, this often results in insufficient folic acid in a woman’s body at this time. If a woman is able to do so after pregnancy, it is best to have her blood folic acid levels tested in the hospital, and if they are low, she may have to take 800 μg of folic acid a day.