The ductus arteriosus (DA) is a normal blood vessel that connects two major arteries
— the aorta and the pulmonary artery — that carry blood away from the
heart in a developing fetus. The DA diverts blood away from the lungs,
sending it directly to the body. The lungs are not used while a fetus is in the amniotic
fluid because the baby gets oxygen directly from the mother's placenta. When a newborn
breathes and begins to use the lungs, the DA is no longer needed and usually closes
during the first 2 days after birth.
If the DA fails to close, a patent (meaning "open") ductus arteriosus is the result.
Oxygen-rich blood from the aorta mixes with oxygen-poor blood in the pulmonary artery,
and too much blood flows into the lungs.
Babies with a PDA may have poor feeding, poor growth, difficulty breathing, excessive
sweating, fatigue, or a bluish color to the skin. A larger PDA puts a strain on the
heart and increases blood pressure in the pulmonary arteries. A smaller PDA may not
cause any symptoms.
Keep in Mind
In the vast majority of babies who have a small PDA but otherwise normal heart,
the PDA will shrink and go away on its own in the first few days of life. Other PDAs
may close on their own within the first year of a baby's life.
Large PDAs are rare, but can strain the heart and cause other problems. Medications,
catheter-based procedures, or surgery may be used to close these PDAs.
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