Kurt Benirschke has once written that the placenta provides the most accurate records of prenatal history of foetus. Our study included 104 placentas obtained from pregnancy complicated by diabetes. An obstetrician did the planimetric estimation directly after delivery. A measurement of lesions was conducted with using a special own idea's morphometric grid that allowed us to evaluate a placental surface and a relative size of change statement in a very quick and convenient way. Our method is very useful for making a quantitative estimation of pathological changes in the chorionic plate of placenta.