Cardiopulmonary complications of pregnancy: radiographic findings.

Physiologic changes during pregnancy affect nearly every organ system. In the thorax, the diaphragm elevates as much as 4 cm because of displacement of the abdominal organs by the gravid uterus, resulting in lower lung volumes. Maternal blood volume and cardiac output increase approximately 45% by mid-pregnancy. Cardiac output can increase as much as 80% during vaginal delivery and up to 50% with cesarean section. These changes result in pulmonary vascular engorgement, progressive left ventricular dilatation, and mild hypertrophy (Fig. 1). Pregnant patients are also prone to a number of pulmonary insults, including infection, aspiration, and neoplastic disease. These abnormalities have several radiographic patterns: cardiogenic and noncardiogenic pulmonary edema, focal pulmonary abnormalities, and extraalveolar air. Radiologists must recognize not only the normal chest radiographic appearance in these patients but also the thoracic complications associated with pregnancy.