The first is to take oral folic acid three months in advance for women, and three months in advance for men to stop smoking, stop drinking and maintain good health. 2. Routine physical examinations and eugenics tests are required. For women, there are four eugenics tests, including toxoplasmosis, rubella virus, herpes simplex virus and cytomegalovirus. Blood type, routine blood tests, liver function, kidney function, blood glucose, blood lipids, infectious diseases, ultrasound examination of the uterus, adnexa and endometrium, routine leucorrhoea examination, mycoplasma and chlamydia tests and thyroid function tests are also performed. If there is a history of bad pregnancies, chromosomal examination is also performed. If the woman has no abnormalities after the examination, she can enter the state of pregnancy preparation. The male partner should have liver function, kidney function, blood glucose, lipid and eugenics tests, as well as a routine semen test. If the male partner also has no abnormalities, he can proceed with the preparation for pregnancy.