Maternal adaptation to pregnancy.

Pregnancy is a time when significant maternal cardiovascular and hemodynamic changes occur. Such alterations may include blood volume, heart rate, stroke volume, cardiac output, and systemic vascular resistance. These physiologic changes are usually well tolerated by the pregnant patient, and they must be recognized and understood by the physician to distinguish them from what is abnormal. Changes begin early in gestation and continue as pregnancy advances, and are totally reversible after delivery. This review summarizes updates on cervical, hemodynamic, cardiovascular and endocrinologic changes during pregnancy.