Pregnancy-induced hypertension: development of a model in the pregnant sheep

Selected hemodynamic, renal, and biochemical parameters were assessed in chronically instrumented third-trimester pregnant ewes and in the same ewes after induction of pregnancy toxemia. Ewes with induced pregnancy toxemia developed hypertension, proteinuria, ketonuria, decreased glomerular filtration rate, decreased cardiac output, and decreased left uterine artery blood flow. Histological and transmission electron microscopy revealed the development of renal morphologic changes consistent with those observed in human pregnancy-induced hypertension. These studies have elucidated that pregnancy-induced hypertension can be produced experimentally in the pregnant ewe. Furthermore, the pathophysiologic features of ovine pregnancy toxemia are similar to those of human preeclampsia, and therefore the sheep provides a suitable animal model to study the human condition, which still remains a major complication of pregnancy, jeopardizing both mother and fetus.