[Quantitative alterations to resorption villi of normal human placentae in the course of gestation (author's transl)].

A total of 45 placentae of different gestatory age were used to study, after clinically and anamnestically normal pregnancy and by a morphometric method, the quantitative behavior of individual parts of the placental barrier in the course of gestation. For this, hematoxylin-stained preparations and enzyme-incubated semi-thin sections were used. The increase in the percentage of fetal vascular surface with a simultaneous decrease in the relative percentage of villous surface (when determining the ratio of villous surface surrounded by maternal blood to the fetal vascular surface) up to the 28th week of gestation must be considered an expression of an increase in the capability of function. The simultaneous distinct decrease in the average number of Langhans cells and the reduction of their less differentiated forms in favor of those showing a higher degree of differentiation allow to make the conclusion that around the 28th week of gestation conditions in individual villi are, in general, similar to those prevailing in term placentae between the 37th and 41st weeks of gestation. The results obtained from the basis of quantitative studies of the placentae of premature infants and babies born at term after different gestatory risks.