The ductus arteriosus is a naturally occurring blood vessel in the fetal heart. Before a baby is born, the ductus arteriosus connects the aorta and pulmonary artery, allowing blood to be pumped from the right side of the heart into the aorta and out to the body, thus bypassing the lungs. This is necessary because the unborn child’s lungs are not functioning, and the developing fetus gets oxygen from the mother’s bloodstream—not the lungs.
At birth, the baby takes his or first breath, and the lungs become active. At this point, the ductus arteriosus is no longer needed and usually closes to prevent mixing unoxygenated blood from the body with oxygenated blood from the lungs.
However, when the ductus arteriosus doesn’t close at birth or by a few days after, unoxygenated blood and oxygenated blood mix, and the overall oxygen level of the blood being pumped to the body drops. This condition is called a patent ductus arteriosus and forces the heart to work harder to supply the body with the oxygen it needs to thrive.
Patent ductus arteriosus is more common among premature babies. It occurs in about eight of every 1,000 premature babies and in about two of every 1,000 full-term births. The condition is twice as common among girls. While genetics might play a role, the cause of this congenital heart defect is not known.
Parents can identify symptoms associated with a patent ductus arteriosus, including rapid breathing, poor eating, shortness of breath, sweating while feeding, tiring easily, and poor growth.
A physician will often hear a heart murmur by listening to the baby’s chest with a stethoscope. This is often the only sign of a patent ductus arteriosus. The doctor can then confirm the diagnosis with an echocardiogram.
Not all babies with a patent ductus arteriosus need treatment. In infants with otherwise normal hearts, the ductus arteriosus might close on its own over time. A small patent ductus arteriosus in a full-term baby might not cause any problems. But if the baby is showing signs of a patent ductus arteriosus, this can be a serious health issue, requiring treatment.
A large patent ductus arteriosus can, over time, make the heart work so hard that the heart enlarges and fluid builds up in the lungs. A patent ductus arteriosus can be more serious in premature infants, who are more likely than full-term babies to have damaged lungs from the heart defect. Increased blood flow through the lungs could reduce blood flow to the rest of the body, which puts other organs at risk for damage.
If the condition doesn’t resolve on its own and needs to be treated, physicians might first use medications to close a patent ductus arteriosus. If medical therapy doesn’t work, they might recommend closure by surgery or via a catheter.
Reviewed by Dr. Sara Connolly, August 2019
- A patent ductus arteriosus occurs when the ductus arteriosus blood vessel doesn’t close properly after birth.
- It is more common in pre-term births and twice as common in girls.
- Sometimes, the condition self-corrects, but it can cause health problems and require treatment if it doesn’t.