1. Marriage and childbirth at the right age. Medical science has proven that the risk of fetal genetic abnormalities increases significantly in pregnant women over the age of 35. Therefore it is best to have children before the age of 35. If this is not possible, then it is recommended that pregnant women of advanced age must undergo strict perinatal medical observation and health care. 2, before preparing to have a child to do a good job of mental and physical state regulation. If the mother-to-be has habits such as smoking and drinking alcohol, it is best to stop at least six months before pregnancy. 3.Strengthen the health care for pregnant women. Especially in early pregnancy actively prevent rubella, influenza and other rubella viral diseases. Pregnant women should try to avoid taking drugs, if they must be used, it must be done under the guidance of a doctor. 4.Minimize exposure to radiation, electromagnetic radiation and other adverse environmental factors during pregnancy. 5.Avoid traveling to high altitude areas during pregnancy. Because it has been found that the incidence of congenital heart disease in high altitude areas is significantly higher than that in plain areas, which may be related to the lack of oxygen.