Pulmonary embolism is a leading cause of maternal death in the United States, contributing to the death of approximately 2 women per 100,000 live births each year. Thrombosis during pregnancy traditionally is treated conservatively with unfractionated heparin or low-molecular-weight heparin; however, cardiovascular collapse associated with a large pulmonary embolus may require immediate aggressive intervention to save the mother and fetus. We report the use of catheter infusion thrombolysis in the successful management of a third-trimester pregnant patient with a hemodynamically significant saddle pulmonary embolus.