A patent ductus arteriosus (PDA) is a type of congenital (present at birth) heart problem. All babies have a small passageway (called the ductus arteriosus) connecting the pulmonary artery and the aorta, which is open at birth.

The pulmonary artery is a blood vessel that moves blood from the heart to the lungs. The aorta is a blood vessel that moves blood from the heart out to the rest of the body. Before birth, the baby gets its oxygen from the mother, so its lungs are not used. The ductus arteriosus is a passageway between the pulmonary artery and the aorta that allows blood in the baby to bypass the unused lungs and carry oxygen to the other organs.

In most babies, the ductus arteriosus closes within a few hours of birth. This is normal. When the ductus arteriosus stays open, blood travels in the wrong direction between the aorta and pulmonary artery. This causes too much blood to flow through the lungs. This can cause problems for a baby, often calling for medical or surgical attention.

Patent Ductus Arteriosus
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In most cases, the cause is not known. However, in a small number of cases, PDA could be caused by exposure during pregnancy to a viral infection, rubella, drugs, or alcohol. In some children, congenital heart disease, including PDA, may be caused by genetic factors.