Pulmonary atresia (uh-TREE-zhuh) is a heart defect present at birth (congenital) that's normally diagnosed within the first few hours or days of life. In pulmonary atresia, the valve that lets blood out of the heart to go to your baby's lungs (pulmonary valve) doesn't form correctly.
Instead of opening and closing to allow blood to travel from the heart to the lungs, a solid sheet of tissue forms. So blood can't travel by its normal route to pick up oxygen from the lungs. Instead, some blood travels to the lungs through other natural passages within the heart and its arteries.
These passages are necessary when your baby is developing in the womb and they normally close soon after birth. Babies with pulmonary atresia typically have a bluish cast to their skin because they aren't getting enough oxygen.
Pulmonary atresia is a life-threatening situation. Procedures to correct your baby's heart condition and medications to help your baby's heart work more effectively are the first steps to treat pulmonary atresia.
Pulmonary atresia care at Mayo Clinic