What is a patent ductus arteriosus?

Ductus Arteriosus: A ductus arteriosus is a vessel that allows babies to survive while in utero... It allows blood to bypass the lungs which are full of amniotic fluid and get to the placenta where gas exchange occurs. A patent ductus arteriosus is simply a vessel that has not closed (patent) once born the lungs relax and the pressures fall. As such, extra blood goes to the lungs, inefficient work for the heart.

Fetal structure: A patent ductus arteriosus (pda) is a small vessel that connects the pulmonary artery to the aorta during fetal life. Once the umbilical cord is cut and we are exposed to an oxygen rich environment that vessel should "shrivel up" and become an unobtrusive ligament. In some people it never closes and in some it will need to be addressed.