1.What is congenital heart disease Congenital heart disease is a cardiovascular disease that is present from birth. Among the onset of congenital heart disease, ventricular septal defect, atrial septal defect, patent ductus arteriosus, pulmonary valve stenosis and tetralogy of Fallot are some of the most common congenital intracardiac malformations in clinical practice. 2, what are the symptoms of congenital heart disease Congenital heart disease can be asymptomatic, and the severity of symptoms is not necessarily proportional to the severity of the disease. Common symptoms of congenital heart disease include cyanosis, chest tightness, shortness of breath, panic, decreased exercise tolerance, syncope, swelling, sweating, dysplasia, recurrent pneumonia, easy to catch a cold, precordial bulge, and heart murmur. In small infants, it is manifested as feeding difficulties, developmental delay, coughing and shortness of breath during feeding, unexplained paroxysmal crying, and cyanosis during crying. 3.What causes precardiac disease The cause of precardiac disease is still not completely elucidated, mainly in the embryonic period by the combined effect of genetic and environmental factors resulting in abnormal development of the heart vessels, the degree of heredity is 55-65%. Most scholars believe that, except for a few precardiac diseases caused by single gene mutations and chromosomal aberrations, most precardiac diseases are polygenic genetic diseases caused by the interaction of genetic and environmental factors, and some studies of families with a high incidence of precardiac disease have confirmed this. Precardiac disease not only involves multiple genes, but also is related to the sequential expression and interaction of these genes at different times and in different spaces. Any qualitative or quantitative abnormalities in the expression of any of these genes may affect the development of the heart and lead to the occurrence of precardiac disease. In addition to genetic factors, there are more environmental factors that cause congenital heart disease. The mother’s older age at pregnancy, the father’s alcohol consumption, the mother’s use of aspirin, tetracycline, birth control pills in early pregnancy, exposure to chemical toxins, and the development of rubella and colds are risk factors for the development of congenital heart disease. In conclusion, the causes of congenital heart disease are complex, and the specific mechanism of its occurrence is still under study. 4, is congenital heart disease hereditary congenital heart disease has certain genetic factors exist, direct relatives have members of congenital heart disease maternal birth of children with congenital heart disease is significantly higher than the normal population, the specific genetic mechanism is still not completely elucidated. But the genetic factors do not necessarily develop, it is also related to environmental factors, early pregnancy infection, medication, radiation exposure and other factors. 5, how to prevent the occurrence of precocious heart disease such as the United States, 90% of pregnant women in prenatal fetal echocardiography, so that the birth rate of children with precocious heart disease significantly reduced. In developed countries to prevent neural tube malformation, the rate of folic acid consumption by pregnant women is very high, and recent studies have shown that a certain amount of folic acid taken before pregnancy can also effectively prevent the occurrence of cardiac malformations. With the rapid economic growth in China in the past 30 years, the impact of environmental factors changes on the occurrence of congenital heart disease should also draw sufficient attention to avoid possible risk factors associated with congenital heart disease, such as early pregnancy infection, family history of congenital heart disease, advanced pregnancy and the impact of radiation, heavy metals, organic solvents, smoking, alcohol abuse, toxins, drugs and other factors. In addition, as a kind of congenital birth defects, attention to eugenics is the most basic preventive measure.