In this study +the purpose to improve diagnostic precision in preclinical forms of late toxemia, the central and peripheral circulation and hemostasis have been evaluated in women during their four day-stay visits scheduled for a pregnancy. Transition of normal pregnancy to "++pre-toxemic" was most commonly seen in the second trimester. Platelet counts and levels of fibrinogen and beta-fibrinogen proved to have the highest predictive value. A decision-making rule was designed for categorization of pregnancies into normal and "++pre-toxemic" and was found to have a 90% efficiency.