Report about evaluation of placenta perfusion studies in 105 females with pregnancies in risk. They were aged between 17 and 48 years and examined during the 27. to 42. week of gestation. Placenta was located after preinjection of 0.1 mCi 113mIn chloride. Examination was performed with a gamma camera, Type NC-HP, and a computing system PDP 11/10 (Gamma 11) on line. Sequential scintigraphy after slow injection of 1.5 mCi 113mIn chloride with 2-seconds-frames over a period of 3 minutes. Performance of histogramm after ROI-contouring of placenta. Half time of the ascending limb of placenta curve is the criterion of perfusion. The mathematical formalism was developed assuming an one-compartment model by Lorenz and Ostertag. Analyzing on the screen by hand we received normal values of half time: 19 +/- 3.4 seconds; using automatical analysis for suitable e-functions developed by Potschwadek we received normal values of half time: 11 less than 1.8 sec.