Smoking may cause the embryo to stop developing, mainly because tobacco contains a lot of toxic substances, such as nicotine or tar and so on, then these toxic substances can be absorbed by the mother, which will make the blood oxygen level drop, so the placenta’s blood oxygen level will also be reduced. The lack of oxygen in the fetus may lead to developmental delays, and in severe cases may lead to the cessation of embryonic development, so it is important for women to avoid smoking when they are pregnant. In addition, smoking may also lead to miscarriage, premature labor or stillbirth, so do not smoke in the clinic, and should also pay attention to second-hand smoke should not be smoked, so as to play a role in eugenics. In addition, it is recommended to strengthen nutrition throughout the pregnancy and not to be exposed to toxic or harmful gases or objects.