[Sudden dyspnoea and facial swelling during labour].

A 25-year-old woman was in the hospital to give birth to her first child. During labour, she suddenly experienced dyspnoea and facial swelling. Palpation revealed crepitus around the face, neck and chest. A chest radiograph showed a continuous diaphragm sign with subcutaneous emphysema, consistent with a spontaneous pneumomediastinum (Hamman's syndrome).