Pulmonary atresia is a defect of the pulmonary valve.
Your pulmonary valve usually controls the blood flow from the lower right chamber of the heart to the main pulmonary artery (the blood vessel that carries blood from the heart to the lungs).
Pulmonary atresia is when this valve doesn’t form, and no blood can go from the right ventricle of the heart out to the lungs.
Most babies with pulmonary atresia will need medication to keep the ductus arteriosus open after birth.
Keeping this blood vessel open will help with blood flow to the lungs until the pulmonary valve can be repaired.