The obstetric literature reflects an increased interest in invasive hemodynamic monitoring during the past decade. While much of this interest has focused on research applications, the patient with severe preeclampsia may benefit clinically from pulmonary artery catheterization under several circumstances. These conditions include severe hypertension unresponsive to conventional antihypertensive therapy, pulmonary edema, persistent oliguria unresponsive to fluid challenge, and in induction of conduction anesthesia in select patients. Theoretical and clinical evidence to support this contention is presented.