Infectious Diseases

Abstract

Prenatal infections are important aspects of placental pathology. They are common and varied. Their pathogenesis and related circumstances must be understood if the pathological lesions are to be interpreted correctly. Many types of infection cause placental changes, but in some types, the infection may be difficult to prove from placental examination. Ultrastructural studies are especially lacking in this area and might be helpful, particularly when virus infection is suspected. Infections may ascend from the endocervical canal, or they may reach the placenta hematogenously through the maternal blood. Rarely are they acquired by amniocentesis, chorionic villus sampling, amnioscopy (Horky and Amon 1967), percutaneous umbilical blood sampling (“PUBS”; Wilkins et al. 1989), or intrauterine fetal transfusion (Goodlin 1965; Scott and Henderson 1972). Many infections cause gross and microscopic changes of the placenta, but others, e.g., the Coxsackie virus infection, leave few characteristic or specifically recognizable traces. This is also the case with parvovirus B19 infection, which often leads to fetal hydrops but has no specific placental alteration other than perhaps intranuclear inclusions in nucleated red blood cell precursors and endothelium, as a report by Hartwick et al. (1989) showed. Samra et al. (1989) described villous necrosis and calcification in the placenta from a 20 weeks’ gestation with hydrops due to this infection (see Chap. 16).