Patent ductus arteriosus, or PDA, is a heart condition that is common in premature babies. Babies born very early have a greater risk of patent ductus arteriosus than babies born closer to term; about half of all micro preemies have a PDA, about 15% of babies born at 30 weeks have a PDA, and only a small percentage of late preterm babies have a PDA.
What Causes a Patent Ductus Arteriosus?
Before birth, a baby’s blood is oxygenated by the placenta, not the lungs. Because of this, the circulatory system of a fetus is very different from that of a newborn baby. A small amount of blood goes to the lungs to nourish them, but most of a fetus’s blood bypasses the lungs completely. Instead of going to the lungs, blood flows through the ductus arteriosus (a hole between the pulmonary artery and the aorta) and out to the rest of the body.
After birth, the baby begins to breathe and the lungs start to oxygenate the blood. When this happens, the PDA should close, allowing blood to flow freely to the lungs. However, when the ductus arteriosus does not close, deoxygenated blood flows through the PDA, into the aorta, and out to the body instead of going to the lungs to become oxygenated.
What Symptoms does a Patent Ductus Arteriosus Cause?
A heart murmur is usually the first symptom of a PDA. A small PDA may not cause any other symptoms, so it is usually not treated. A larger PDA can cause other symptoms, including:
- Low oxygen saturation
- Fast or labored breathing
- Poor feeding
- Bounding (very strong) pulses
- Weight loss
How is a Patent Ductus Arteriosus Diagnosed?
Doctors and nurses may suspect a PDA when a baby has a heart murmur, especially if the baby is also breathing fast, has bounding pulses, and periods of low oxygen saturation. If a patent ductus arteriosus is suspected, an echocardiogram of the heart will be ordered. Also called a cardiac echo, this painless test is a sonogram of the heart.
How is a Patent Ductus Arteriosus Treated?
Most small PDAs will close on their own, with no treatment. Unless a baby is having a lot of symptoms from a PDA, doctors will simply monitor the baby closely and wait for the ductus arteriosus to close. A baby may be put on fluid restriction while doctors wait for a PDA to close. This helps reduce the symptoms of a PDA because the heart has less blood to pump and doesn’t have to work as hard.
If a PDA is causing a lot of symptoms, then doctors will try to treat it with medication. NeoProfen, a special form of ibuprofen, is the medication most commonly used to close a PDA. In fact, that’s one reason why moms in their third trimester of pregnancy should stay away from ibuprofen - the fetus needs to have an open ductus! If NeoProfen doesn’t work, doctors may try another medication called Indocin.
In some cases, surgery may be needed to close a PDA. Called PDA ligation surgery, this is a relatively common surgical procedure that usually has very good results.
Organization of Teratology Information Specialists. "Ibuprofen in Pregnancy." Retrieved July 23, 2010 from http://www.otispregnancy.org/files/ibuprofen.pdf
National Heart, Lung, and Blood Institute. "Patent Ductus Arteriosus." Retrieved July 22, 2010 from http://www.nhlbi.nih.gov/health/dci/Diseases/pda/pda_what.html
Medline Plus. "Patent Ductus Arteriosus." Retrieved July 22, 2010 from http://www.nlm.nih.gov/medlineplus/ency/article/001560.htm