Every baby is born with a ductus arteriosus.
Then it picks up a fresh supply of oxygen. If it doesn't, some blood that should have gone through the aorta and on to nourish the body goes back to the lungs. Failure of the ductus to close is quite common in premature infants but fairly rare in full-term babies. If the ductus arteriosus is large, a child may tire quickly, grow slowly, catch pneumonia easily and breathe rapidly. In some children, symptoms may not occur until after the first weeks or months of life.