[Studies on placental blood flow under drug induced hypertension (animal experiments) (author's transl)]

Placental blood-flow rates in rabbits were measured by the indirect method of local apparent conductivity. In our experiments, hypertension was produced by injection or infusion of hypertensive drugs. As a result of hypertension we observed a marked decrease in placental blood flow. Vasoconstriction seems to be the pathophysiologic mechanism causing the reduced blood flow rate. Accordingly, the placenta may not be considered as a "priviledged organ" in circulatory regulations. In our experiments, placental ischemia subsequently to ligatures did not produce hypertension so that the production of a placental pressor-substance could not be demonstrated. If we assume a circulus vitiosus hypertension-placental ischemia-hypertension, the hypertension seems to be the primary cause.