PDA

Patent ductus arteriosus: The ductus arteriosus is a blood vessel connecting the pulmonary artery to the aorta normally present in a fetus.  Its purpose is to provide a circulatory by-pass of the lungs for the blood which are , allowing blood to bypass the lungs that are not yet functional in the womb. This by-pass normally closes at the time of birth since it is no longer needed but when this does not occur the resulting condition is termed a patent ductus arteriosus, abbreviated PDA.