[The pathogenesis of uterine hemorrhages in the so-called placental polyps].

On the basis of histological and immunohistochemical studies of 50 uterine scrapes after abortions and labor due to late bleedings, the authors identified three major types of the so-called placental polyps: (a) preserved villi (56%); (b) clusters of destructive villi (38%); (c) isolated viable cotyledons (6%). Two pathogenetic mechanisms of uterine hemorrhages have been substantiated: firstly, preservation of the brush border of a syncytiotrophoblast (including the presence of placental phosphatase) maintains the anticoagulative properties of villi; this appears in cases of postabortion hemorrhages and at the most in preserved cotyledons. Secondly, the thromboplastic properties of the preserved villi play a leading role in the pathogenesis of uterine hemorrhage in the scrapes where necrotic villi with epithelial remains are prevalent, i.e. the situation is similar to the hypocoagulative phase of isolated chronic disseminated intravascular coagulation.