Congenital cardiovascular defects occur when the heart or the heart's surrounding blood vessels develop improperly before birth. Most heart defects either obstruct blood flow in the heart or in the vessels around it or cause abnormal blood flow patterns through the heart. There are many ways that the heart can develop improperly.
Heart defects are the leading cause of birth defect related deaths.
The problem of congenital cardiovascular defects affects about one percent of live births and is the most frequent of the congenital malformations in newborns. Over 25,000 infants enter this world with heart defects in the United States alone each year. These defects can be caused by a number of different factors, but for the most part, physicians do not know the exact cause of most congenital cardiovascular defects. Sometimes a viral infection or even contracting German measles by the mother during pregnancy may affect the development of the baby's heart. Heredity is also thought to play a role in congenital cardiovascular disease.