The ductus arteriosus is a blood vessel that allows blood to bypass a babies’ lungs while they are in the womb. This is because their lungs are underdeveloped until they start breathing. The ductus arteriosus therefore acts as a ‘safety feature’ and is biologically programmed to shut when babies are born at full-term.
The closure usually happens in the first few days or weeks after birth. If it remains open, it is known as patent ductus arteriosus (PDA).
More information for parents about patent ductus arteriosus