For the health of the fetus, most women with a history of smoking are required to quit smoking completely during the preparation for pregnancy and are prohibited from smoking after pregnancy. Including men need to quit smoking and drinking during the preparation period to improve the quality of sperm. Cigarettes contain a lot of tar, nicotine, carbon monoxide and other toxic and harmful substances. Smoking after pregnancy, inhalation of toxic and harmful substances can pass through the placenta into the fetus, and lead to the fetus to develop poorly, intrauterine hypoxia, backward brain development and other adverse reactions. Women should not only quit smoking but also take oral folic acid, pay attention to rest, avoid exposure to toxic and radioactive substances, etc., and maintain good living habits and prohibit smoking after pregnancy.