Unexpected second trimester pregnancy loss due to maternal parvovirus B19 infection.

Five unexplained second trimester fetal deaths occurring in a 3-month interval were evaluated to determine whether the fetal demise was associated with maternal infection due to parvovirus B19. One fetus was markedly hydropic, a classic finding of fetal infection; no gross anomalies were present in the other four. Liver specimens from all five fetuses showed viral inclusions by light microscopy, supporting the presence of fetal parvovirus B19 infection. None of the five women had a history of parvovirus infection, but serum samples from all of them were positive for IgG to parvovirus. We conclude that maternal parvovirus B19 infection is associated with fetal demise during the second trimester and that hydropic changes may be absent, necessitating careful evaluation of tissue from the dead fetus.