Cytomegalovirus infection and fetal death in a twin. A case report.

In a diamnionic-dichorionic male twin pregnancy, one twin was stillborn, with disseminated cytomegalovirus (CMV) identified morphologically, and the other was liveborn, without clinical or laboratory evidence of CMV infection. The placenta of the affected twin had chronic villitis; that of the liveborn was normal. Although the discordance went unexplained, it illustrates the clinical variability of congenital CMV infection. Dissimilar immune responses between the affected and unaffected twin or direct extension of uterine CMV infection to only one twin may have been responsible for the discordance.