Before preparing for pregnancy, couples need to undergo routine physical examinations to rule out the possibility of having some disease in the body that could prevent pregnancy. Routine tests include routine blood tests, urine tests, gynecological examinations, routine white belt tests, cervical discharge tests, ABO blood group and RH blood group tests for women. In addition, there are liver function, hepatitis B virus markers and syphilis serology, and HIV antibody test. Men should have a routine examination of semen, as well as a basic physical examination such as routine blood and urine tests, and when the physical examination is clear, they can officially prepare for pregnancy. Three months before preparing for pregnancy, women should take folic acid, and both spouses should quit smoking and control alcohol consumption. Also, it is best to pay attention to this time not to dye your hair, get your nails done and not to be exposed to harmful substances, such as aluminum, mercury and other heavy metals.