The main purpose of preparing for pregnancy by taking oral folic acid tablets 3 months before preparing for pregnancy is to prevent fetal neural tube malformations. There are many folic acid tablets in clinical practice, and only small doses of folic acid tablets will prevent fetal neural tube malformations, for example, 0.4 mg of folic acid tablets are more commonly used in clinical practice, once a day, one tablet at a time, for 3 consecutive menstrual cycles. It is also recommended to take 1 tablet of folic acid daily during the first 3 months of pregnancy to effectively prevent fetal neural tube abnormality. In addition, it is best to quit smoking and drinking during the preparation period, live a regular life and enhance nutrition.