The causes of congenital heart disease can be broadly divided into three aspects: genetic factors, environmental factors and disease drug factors. 1, genetic factors: Take trisomy 21 as an example, about 50% of patients with this disease have congenital heart disease, of which endocardial cushion defect and ventricular septal defect account for 32% and 29% respectively, followed by atrial septal defect accounting for 11%, tetralogy of Fallot accounting for 7.9% and end ductus arteriosus accounting for 6.7%. Most of the cases of pure atrial septal defect, ventricular septal defect, patent ductus arteriosus, and tetralogy of Fallot are polygenic in nature, and the risk of reoccurrence of siblings and children of the first patients is about 4%. Environmental factors: refers to the environment in which the pregnant woman lives before and during pregnancy, including the living and working environment. Environmental factors include chemical factors and physical factors. Chemical factors are mainly long-term exposure to harmful chemicals, including benzene, sulfur dioxide and other harmful gases and heavy metals such as mercury and cadmium. Therefore, pregnant women should avoid living in newly renovated houses, as well as avoiding exposure to chemical factors and strengthening protection. Physical factors are mainly radiation, because radiation has pathogenic effect on human body and teratogenic effect on fetus. According to the analysis results of some medical studies, drug and disease factors include alcoholism of the mother, aspirin, tetracycline, birth control pills, rubella and cold. These are all high risk factors for congenital heart disease in children. Therefore, it is important that mothers avoid drugs and discontinue high-risk medications during pregnancy, especially in early pregnancy. This should be the primary prevention measure for congenital heart disease. The mother should also avoid colds and bacterial and viral infections such as rubella and measles in early pregnancy, because bacterial and viral infections can also cause malformations in fetal development and congenital heart disease. In addition, advanced maternal age is also a high risk factor for congenital heart disease in the fetus. Experts suggest that for genetic factors, parents who have a family history of genetic diseases should try to rule out the possibility of congenital heart disease in their fetus through chromosome examination and genetic examination during pregnancy; in addition, to prevent the occurrence of congenital heart disease pregnant women should avoid living in newly renovated houses, avoid exposure to chemical factors; avoid exposure to radioactive substances, and avoid living in an environment with strong electromagnetic waves; Avoid the use of drugs and prohibit high-risk medications as much as possible. Tips: What should pregnant women do if they have a cold or rubella? Bacterial and viral infections can lead to malformations in fetal development and cause congenital heart disease. Therefore, pregnant women should also avoid colds and bacterial and viral infections such as rubella and measles. In case of colds and infections with rubella and measles, they should consult a professional doctor promptly and not take medications indiscriminately.