Folic acid is a medicine to prevent fetal malformations and can be stopped when the fetus is fully developed in the third month of pregnancy. It should be taken from the time of pregnancy preparation until the third month of pregnancy, during which time it should be taken according to the instructions. In the fourth month, the fetus is the fastest growing and developing period, so it should be supplemented with calcium in a timely manner. The occurrence of such diseases. During this period, you can eat more seafood, seaweed, seaweed and other foods, and you should also pay attention to more sunshine to promote the absorption of calcium.