[Pathology of the placenta. VII, Inflammation of the placenta]

A general account of routes of infection is followed by reference to localisations of placental infection. The most common routes of infection are transmembrane, transdecidual, haematogenico-maternal, and haematogenico-foetal. Intra-uterine infections with placental involvement may be caused by several types of pathogens, with particular reference being made to listeriosis, tuberculosis, and lues, while virus infections may be associated with rubella and cytomegaly and protozoonosis with toxoplasmosis. Unambiguous morphological traces are left in the placenta merely by few of these "specific" infections. A possible pathogen, therefore, can be rarely concluded from the type of inflammatory placental involvement. Reference is also made to "villitis of unknown aetiology", an aetiologically obscure, probably haematogenico-maternal infection of the placenta. Introduction of this term to histological routine diagnosis is recommended. This account of placental inflammation is completed by explanations on relationships between inflammation and impaired maturation of the placenta as well as between inflammation and intervillous fibrin deposition or chronic disorders of intervillous circulation.