Congenital unilateral pulmonary hypoplasia is a rare abnormality characterized by the underdevelopment of a lung on one side of the chest. This disorder often occurs along with other congenital abnormalities.

Symptoms of congenital unilateral pulmonary hypoplasia include an asymmetry of the chest with a bell-shaped chest deformity, restricted chest wall expansion, reduced breathing on the affected side, rapid, shallow breathing, and respiratory distress.

Treatment for congenital unilateral pulmonary hypoplasia begins before an infant is born with the use of a combination of corticosteroids, antibiotics, and tocolytics or an amniopatch consisting of an intraamniotic injection of platelets and cryoprecipitate. After birth, treatment may include respiratory support with supplemental oxygen, mechanical ventilation, or extracorporeal membrane oxygen (ECMO). In most cases, congenital unilateral pulmonary hypoplasia is fatal. Individuals who survive often have chronic lung disease, which may be treated with bronchodilators, antibiotics, chest physiotherapy, and prophylactic vaccinations. In some cases, surgery may be necessary to remove damaged lung tissue (bronchiectasis) from recurrent respiratory infections.