Spontaneous pneumomediastinum is the presence of free air contained within the mediastinum, frequently associated with subcutaneous emphysema and of atraumatic origin. Frequency during childbirth is 1 in 100,000. We report the case of a 19 year old woman without respiratory disease history, in her first pregnancy with 39.5 weeks of gestation patient had, prolonged latent phase and sudden postpartum onset of dyspnea, thoracic pain and subcutaneous emphysema. Simple X ray film and thoracic tomography revealed the presence of free air in the mediastinum. The association of pneumomediastinum during delivery is an uncommon event.