Villitis of unknown aetiology: its incidence and significance in placentae from a British population.

A histological study of 1000 randomly selected placentae from women delivered in Manchester, UK, revealed 136 cases of villitis; this is a higher incidence than that recorded in Australia and North America but lower than that noted in South America. There were no obvious clinical differences between mothers whose placentae showed a villitis and those in a control group whose placentae were free of villitis. As in other studies, there was an association between the presence of a villitis, particularly severe villitis, and fetal intrauterine growth retardation. The nature of this association cannot, however, be clarified until the aetiology of villitis is determined.