Single cytomegalovirus strain associated with fetal loss and then congenital infection of a subsequent child born to the same mother.

BACKGROUND Intrauterine transmission of cytomegalovirus (CMV) can occur even in CMV-seropositive mothers. Previous studies demonstrated re-infection with a newly acquired CMV strain during pregnancy had a major role in such transmission. Although reactivation of latently infected CMV is another plausible cause, no direct evidence has been documented. OBJECTIVES We sought to identify the route(s) and maternal risk factor of CMV infection that occurred in consecutive pregnancies and resulted in symptomatic congenital infections. STUDY DESIGN A newborn identified with congenital CMV infection in our newborn screening program developed hearing loss and subsequent nystagmus. The mother had a history of an elective abortion due to a severe fetal CMV infection 32 months prior to delivery of this newborn. We analyzed maternal serological changes and compared CMV genomic sequences in specimens obtained from the aborted fetus and the present case. We also analyzed immunological functions of the mother. RESULTS Our major findings were as follows: (1) the aborted fetus and the present case were infected with the same strain. (2) The congenital infection that resulted in the abortion was due to a primary infection. (3) CMV DNA was undetectable in the mother's blood from 3 months after the abortion. These results strongly suggested that maternal viral reactivation caused the congenital infection in the present case. However, we could not find impairment of immunological functions in the mother. CONCLUSIONS Viral reactivation in an apparently immunocompetent mother can cause symptomatic congenital CMV infection.