Once babies are born, they're expected to breathe on their own, a task their mothers handled for them in the womb. That transition from womb support to independent breath involves a short blood vessel known as the ductus arteriosus. Before the baby is born, the ductus arteriosus connects the aorta and the pulmonary artery, serving as a lung bypass. Shortly after birth, the ductus arteriosus closes, and the major arteries start delivering blood to the lungs to pick up oxygen.
In premature babies, however, the ductus arteriosus often remains patent, or open, resulting in abnormal blood flow. The disrupted blood flow strains the heart and the lungs, and left unchecked, it could lead to heart failure. A baby with PDA might have a hard time breathing and eating. You may also notice the baby sweating while eating and getting tired easily. The diagnosis can be confirmed if the doctor hears a heart murmur. In some cases, doctors will advise watchful waiting, since the ductus arteriosus can close on its own. Other times, medications or corrective surgery may be required.