摘要: In pregnancy, the blood volume increases by about 1500 mL mainly because of expansion plasma volume. fact, may increase 10% 7 weeks pregnancy. The red cell mass also increases, but not in proportion to change This results physiologic anemia which is maximal 30 32 weeks. pressure (BP) decreases reach a nadir at 28 gestation. decrease BP caused lower systemic vascular resistance. result an cardiac output and heart rate. Thus hemodynamic changes pregnancy are characterized primarily