The cardiovascular complications of pregnancy.

During the course of a normal pregnancy, the cardiovascular system of the mother is required to adapt to significant alterations in hemodynamics, including an almost 50% increase in cardiac output. This change in cardiac output is mediated by a significant increase in heart rate, a change in blood volume, as well as a neurohormonally mediated increase in vasodilatation. Simultaneously, significant changes occur in other organ systems, which also affect the cardiovascular system. For instance, there are increases in erythropoiesis to increase red cell mass, increased production of procoagulant factors, and profound activation of the collagenolytic system. To discuss the multitude of cardiovascular complications that can occur during pregnancy, we must understand the adaptations required in the cardiac, hematologic, and musculoskeletal systems. The purpose of this review is to delineate the adaptations required by each organ system and to review the complications that result when maternal physiology is unable to make the required adaptations.