[The colloidosmotic pressure (cop) as a parameter of maternofetal fluid exchange (author's transl)].

Colloidosmotic pressure (COP), osmotic and hydrostatic pressures are important parameters in passive maternofetal fluid exchange. Using a new method (Hansen-/Knauer-Osmometer), COP-measurements were carried out on maternal blood plasma (COP 355 +/- 55 mmH2O), fetal plasma (COP 290 +/- 51 mmH2O) and amniotic fluid COP 12.6 +/- 5.8 mmH2O) obtained of 30 pregnant women during delivery at term. The interpretation of the resulting pressure gradients must consider physiochemical properties of protein solutions and the "selectivity" of biologic and artificial membranes. Membrane osmometry registers pregnancy-specific protein alterations, yields additional information concerning the physiology and pathology of fluid exchange, and may continue advanced development of kybernetic model conceptions.