What is a congenital cardiovascular defect?

Congenital means inborn or existing at birth. Among the terms you may hear are congenital heart defect, congenital heart disease and congenital cardiovascular disease. The word "defect" is more accurate than "disease." A congenital cardiovascular defect occurs when the heart or blood vessels near the heart don't develop normally before birth.

What causes congenital cardiovascular defects?

Congenital cardiovascular defects are present in about 1 percent of live births. They're the most common congenital malformations in newborns. In most cases scientists don't know why they occur. Sometimes a viral infection causes serious problems. German measles (rubella) is an example. If a woman contracts German measles while pregnant, it can interfere with how her baby's heart develops or produce other malformations. Other viral diseases also may cause congenital defects.

Heredity sometimes plays a role in congenital cardiovascular defects. More than one child in a family may have a congenital cardiovascular defect, but this rarely occurs. Certain conditions affecting multiple organs, such as Down's syndrome, can involve the heart, too. Some prescription drugs and over-the-counter medicines, as well as alcohol and "street" drugs, may increase the risk of having a baby with a heart defect. Researchers are studying other factors.

What are the types of congenital defects?

Most heart defects either obstruct blood flow in the heart or vessels near it, or cause blood to flow through the heart in an abnormal pattern. Rarely defects occur in which only one ventricle (single ventricle) is present, or both the pulmonary artery and aorta arise from the same ventricle (double outlet ventricle). A third rare defect occurs when the right or left side of the heart is incompletely formed - hypoplastic heart.