1. Pulmonary hypoplasia can be caused by structural defects in lung development, vascular abnormalities, or biochemical issues. It results in reduced lung size and function. 2. It can be diagnosed antenatally by ultrasound or postnatally based on severity of respiratory distress and symptoms. Testing includes measuring lung volumes and function. 3. Management depends on severity but generally involves respiratory support, maintaining blood pressure and oxygen levels, treating pulmonary hypertension, and ruling out other causes of respiratory distress. Prognosis depends on the underlying cause but severe cases often do not survive.