[Diagnosis and management of a foetus with congenital high airway obstruction syndrome (CHAOS)].

Congenital high airway obstruction syndrome is a rare malformation whose prognosis is very poor resulting in foetal or perinatal death if no perinatal intervention is performed. However, ultrasound and magnetic resonance enable an accurate prenatal diagnosis and optimal choice of interventional foetal medicine techniques (transtracheal puncture, fetoscopy). These approaches reduce foetal side effects related to the pathological process, and avoid the mother ex utero intrapartal treatment and its deleterious effects.