Since congenital heart disease is brought from the mother’s womb, it is closely related to the intrauterine environment, or, rather, to the mother’s body. If during pregnancy (mainly in the first trimester) the mother has a viral infection, especially rubella, mumps, or influenza, it is likely to cause fetal heart malformation, because the heart develops and takes shape in the first trimester; too many sedative drugs, antibacterial agents (mainly tetracycline, oxytetracycline, and chlortetracycline), and quinine for the pregnant mother are also a cause; the mother suffers from The fetal heart may not develop properly when the mother has “diabetes” or “hyperthyroidism”; multiple births in older women are prone to congenital heart disease and other malformations; exposure to radiation during pregnancy, lack of folic acid in the diet, poor mood of the pregnant woman In addition, we can also see that in the same family, twins or several children have congenital heart disease or other malformations, and when one of the family members has heart disease, the greater the chance of the child having congenital heart disease. All these conditions indicate that congenital heart disease is related to heredity. During pregnancy, it is beneficial for the mother to avoid the above-mentioned unfavorable factors, especially to prevent viral infections and to take as little medicine as possible (including herbal medicine), which can prevent malformations in fetal heart development.