The main effects of smoking and drinking on pregnancy preparation are that they may lead to spontaneous abortion after pregnancy, poor fetal development, and increase the incidence of pregnancy complications. 1. Spontaneous abortion: Smoking and drinking during pregnancy may lead to fetal malformations and chromosomal abnormalities, which are important risk factors for spontaneous abortion. 2. Fetal dysplasia: Smoking and heavy alcohol consumption by pregnant women may also lead to low birth weight, preterm labor, and fetal malformations. 3. Complications of pregnancy: History of smoking and alcohol consumption and family history of diabetes or hypertension are independent risk factors for gestational diabetes mellitus combined with hypertension. Therefore, it is recommended to avoid smoking and alcohol consumption during pregnancy and the pre-pregnancy period, especially for those with a family history of diabetes or hypertension. To minimize and avoid risky events, women should stop smoking and drinking during pregnancy and pre-pregnancy. Prompt cessation of smoking and limiting alcohol consumption are recommended in daily life.