An antenatal diagnosis: Congenital high airway obstruction.

Congenital high airway obstruction (CHAOS) is a rare lethal fetal malformation characterised by obstruction to the fetal upper airway, which can be partial or complete. Antenatal diagnosis of CHAOS is important due to recent management options. Diagnosis is made with secondary changes such as hyperechoic enlarged lungs resulting in mediastinal compression, ascites, hydrops, flattened or everted diaphragms and dilated distal airways. We reported a case of CHAOS, antenatally on ultrasonography (USG) at 20 weeks of gestation.