Pneumomediastinum in pregnancy: two case reports and a review of the literature, pathophysiology, and management.

Pneumomediastinum, free air trapped in the mediastinal connective tissue, is a rare complication of pregnancy, occurring most frequently in the second stage of labor. Symptoms are often not noted until after delivery. Occurrence before and in the first stage of labor, as seen in the two cases reported here, is more uncommon. One case history is the first report of the coexistence of pneumomediastinum and pneumothorax in pregnancy. The prognosis for spontaneous pneumomediastinum in pregnancy is favorable. Pathophysiologic mechanisms, diagnosis, and management are discussed, and a review of the literature is presented.