What Is Patent Ductus Arteriosus?

Patent ductus arteriosus (PDA) is a heart problem that occurs soon after birth in some babies. In PDA, there is an abnormal circulation of blood between two of the major arteries near the heart. Before birth, the two major arteries—the aorta and the pulmonary artery—are normally connected by a blood vessel called the ductus arteriosus, which is an essential part of the fetal circulation. After birth, the vessel is supposed to close within a few days as part of the normal changes occurring in the baby's circulation. In some babies, however, the ductus arteriosus remains open (patent). This opening allows blood to flow directly from the aorta into the pulmonary artery, which can put a strain on the heart and increase the blood pressure in the lung arteries.

Figure A shows the normal anatomy and blood flow of the interior of the heart. Figure B shows a heart with a patent ductus arteriosus. The defect connects the aorta with the pulmonary artery, allowing oxygen-rich blood from the aorta to mix with oxygen-poor blood in the pulmonary artery.

A PDA is a type of congenital heart defect. A congenital heart defect is any type of heart problem that is present at birth.

If your baby has a PDA, but has an otherwise normal heart, the PDA may shrink and go away completely, or it may need to be treated to close it. But, if your baby is born with certain types of heart defects that decrease blood flow from the heart to the lungs or the body, medicine may be given to keep the ductus arteriosus open to maintain blood flow and oxygen levels until corrective surgery for the heart defect(s) can be performed.

About 3,000 infants are diagnosed with PDA each year in the United States. It is more common in premature infants (babies born too early) but does occur in full-term infants. Premature babies with PDA are more vulnerable to its effects. PDA is twice as common in girls as in boys.

The next section, How the Heart Works, provides a more detailed description of a heart with a PDA compared to a normal heart. See that section for a more detailed description of the anatomy and circulation of a normal heart.

December 2007