Atresia (ah-TREE-zhah) is a condition in which a baby is born with a missing or closed valve or tube somewhere in his or her body.

Pulmonary atresia is a rare defect in which a baby is born with an abnormally developed pulmonary heart valve (which is between two of the heart's chambers) that doesn't open. This prevents blood from flowing through the heart and into the lungs to receive oxygen. Treatments include medications and surgery.

More to Know

Air, blood, bodily fluids, and waste products travel throughout the body in a system of vessels, tubes, and chambers that are often separated by valves. When a child is born with atresia, it means that a valve is missing or a tube is closed off. This interrupts the normal flow of blood, fluid, waste, or air, which can lead to a number of complications.

Most kinds of atresia are serious and can be fatal if they go untreated. Treatment usually involves surgery while the child is still an infant.

Atresia can affect many body parts, including the nose, ears, organs, digestive tract, and heart. The types of atresia are named for the body parts they affect:

• Tricuspid atresia and aortic atresia also involve valves in the heart.
• Biliary atresia is a defect in the liver or bile system.
• Choanal atresia is a defect of the nasal passages (choana).
• Anal atresia (imperforate anus) and esophageal atresia are defects of the digestive tract.

Keep in Mind

Most kinds of atresia can be treated successfully with surgery; some cases may require more than one operation.

All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.