title: [Morphogenesis of human placenta in the first trimester of gestation].
abstract: On the basis of morphometric and immunohistochemical study of placental villi obtained from 45 cases of medicinal and medical abortions in healthy women, the new data on placentation are presented with the discrimination of three stages of placental morphogenesis. The first stage (weeks 4 and 5 after fertilization) included a differentiation of villous chorion (chorion frondosum). It was characterized by high mitotic activity of villous cytotrophoblast and intensive vasculogenesis in the villous stroma. The second stage (weeks 6 and 7) included capillary development (angiogenesis) and formation of vascular communications within a "placenta-embryo" subsystem functioning in low-oxygen level environment. The third stage (weeks 8 and 9-10) was characterized by vascular bed formation in "mother-placenta" subsystem and by the beginning of more effective hemochorial embryo and fetal metabolism. As a result of placentation, hemodynamics formation in "mother-placenta-embryo" system was completed, which is a necessary condition for further fetal development.
authors.forename: A P
authors.initials: AP
authors.lastname: Milovanov
authors.forename: L M
authors.initials: LM
authors.lastname: Erofeeva
authors.forename: I A
authors.initials: IA
authors.lastname: Zolotukhina
authors.forename: N V
authors.initials: NV
authors.lastname: Aleksandrovich
mesh_terms: D002824:Chorionic Villi / Q000196:embryology / Q000254:growth & development; D005260:Female; D006801:Humans; D009024:Morphogenesis; D018919:Neovascularization, Physiologic / Q000502:physiology; D010929:Placentation / Q000502:physiology*; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000502:physiology*