This paper reviews the technique of nuclear placental flow-rate determination developed in 3 stages at the I. Department of Obstetrics and Gynaecology, University of Vienna. It particularly highlights the diagnostic potential of the most recent development, which is based on iterative regression, by quoting pertinent figures. In 153 females with type I flow-rate patterns the diagnosis proved to be correct in 82.2% of cases. 26 patients had pathological flow-rate patterns and 20 of the infants born to this group of mothers had moderate to severe dystrophy due to reduced placental function. The placental perfusion test, another recent development, is of particular significance in differentiating between the causes underlying reduced placental blood flow. These two techniques have internationally conquered a firm position in the battery of placental perfusion studies designed to assist in the diagnosis and treatment of placental insufficiency.