Patent ductus arteriosus is a specific type of congenital heart defect that may occur in newborns soon after their birth. Ironically, prior to birth, the condition is normal and necessary. After birth, however, it is abnormal and threatening to the baby's health.
-
Fetal Circulation
-
Since unborn babies are not required to breathe on their own, they possess a shunt, or ductus arteriosus, that connects the pulmonary artery, which delivers blood to the lungs, to the aorta, the major blood vessel that sends blood to the body. As a result, much of the fetal circulation bypasses the lungs.
Infant Circulation
-
After birth, the infant's lungs, rather than the mother's lungs and placenta, become responsible for oxygenating the blood. Consequently, the ductus arteriosus closes to allow more blood flow to the lungs, where the blood obtains necessary oxygen. In some cases, the shunt does not close, a condition called patent ductus arteriosus.
Prostaglandins
-
Prostaglandins are chemicals produced by the ductus arteriosus of the unborn child that cause the structure to remain open. After birth, the baby's first breath initiates a series of reactions, one of which is decreased prostaglandin production. The decreased levels of prostaglandin result in closure of the ductus arteriosus.
Extraordinary Circumstances
-
Sometimes babies are born with other structural defects that prevent normal circulation to the lungs or the body. In these cases, doctors want to keep the ductus arteriosus open after birth until they can repair the abnormalities. Although the ductus arteriosus does not provide a large amount of blood flow to the areas, it does provide some. In these cases, doctors prescribe prostaglandins for the babies to keep the ductus open until normal circulation can be established.
-