[Rheology and gravidic hypertension]

Gestational hypertension is the development of hypertension and proteinuria after the 20th week of gestation. The most common causes of increased peripheral resistance are the vasoconstriction and hemoconcentration with plasma volume contraction. Additional rheological parameters are an elevated red blood cell aggregation and impaired erythrocyte deformability. Preeclamptic patients showed a significantly low cardiac output and central venous pressure than normal pregnant women. It has already been shown by the studies by Hytten and Paintin (1963) and also by the subsequent studies by Garn et al. (1981), Murphy et al. (1986) that a strong correlation exists between newborn weight and plasma volume. Other authors (Gallery et al. (1979/1981)) show the possibility that plasma volume contraction plays an even larger role than vasoconstriction in the fetal growth retardation that often accompanies maternal hypertension. This possibility is supported by the finding that hypertension and perinatal complications can be reduced in some pregnant women by the admission of oncotic solutions (i.e. hydroxyethyl-starch) that expand plasma volume. Volume expansion with hydroxyethyl-starch appears to be of therapeutic benefit for hypertensive patients and patients with fetal growth retardation with low cardiac output.