Involution of Implantation Site and Retained Placenta

  • Kurt Benirschke
  • Peter Kaufmann


Pathologists rarely obtain a postpartum uterus for a detailed study of the involutional changes that take place at the former site of implantation. Therefore involution of the normal placental site has been studied by only a few investigators. Normally, the postpartum lochia contain the decidual remnants, including perhaps the remains of the vasculature that had previously undergone the so-called physiological changes of pregnancy. Only when significant postpartum hemorrhage occurs and hysterectomy becomes necessary is the pathologist asked to seek the cause of the bleeding. He or she may then find remains of villi, incompletely thrombosed vessels, “placental polyps,” and some degree of inflammatory reaction. These areas are difficult to study objectively because most pathologists have no experience with the normal, complex process of placental site involution. Williams (1931), in a classical paper, attempted to rectify this situation. His study should be read before any interpretation of such postpartum uteri is undertaken. It must also be recognized that in 85% of normal, delivered placentas the decidua basalis shows foci of polymorphonuclear leukocyte infiltration (Schneider, 1970). These cells are part of an apparently normal process of implantation and are not considered an expression of deciduitis or infection.


Placental Tissue Implantation Site Placenta Accretas Placental Site Stromal Fibrosis 
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Copyright information

© Springer Science+Business Media New York 1995

Authors and Affiliations

  • Kurt Benirschke
    • 1
  • Peter Kaufmann
    • 2
  1. 1.University Medical CenterUniversity of California, San DiegoSan DiegoUSA
  2. 2.Institut für Anatomie der Medizinischen FakultätRheinisch-Westfälische Technische Hochschule AachenAachenGermany

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