The ductus arteriosus is a vital blood vessel in fetal circulation that connects the pulmonary artery to the descending aorta, allowing most blood to bypass the fetal lungs, which do not function for breathing before birth. On fetal echocardiography, the ductus arteriosus is routinely visualized and evaluated to ensure normal flow direction and velocity. After birth, this vessel normally closes within the first few days of life as the newborn begins breathing and the lungs take over gas exchange. When the ductus arteriosus fails to close, the condition is called patent ductus arteriosus, or PDA, and can be detected and monitored with echocardiography.
Sonography Term