Placental morphology in cytomegalovirus infection

Three groups of placentae from 27 cases of cytomegalovirus infection were examined morphologically and by specific immunofluorescence. Placentae in Group 1 (four cases) had a mean gestational age of 24.5 +/- 2.5 weeks; those in Group 2 (11 cases) had a mean gestational age of 36.4 +/- 2.7 weeks; those in Group 3 (12 cases) had a mean gestational age of 40 +/- 1.8 weeks. A tendency towards increased placental weight was observed. In 23 cases, a haematogenous placentitis was suspected on gross examination. Some specific features were detected on light microscopy. In Group 1 the lesions were represented by pronounced dysmaturity of villous structures, diffuse reparative villitis and intervillitis allied to an abundance of cytomegalic cells and areas of necrosis and calcification. In Group 2 a chronic active process was indicated by the presence of vascular involvement, proliferative-necrotic and reparative villitis and fresh villous necrosis; cytomegalic cells were scarce. In Group 3 placentae there was a predominance of villous plate lesions similar to those found in the septicaemic phase of maternal infections; necrotizing, proliferative and, rarely, reparative villitis was present; cytomegalic cells were rare. We may conclude that placental morphology needs to be substantiated by special laboratory techniques for the detection of cytomegalovirus infection.