Clinical manifestations and outcomes of parvovirus B19 infection during pregnancy in Japan.

Parvovirus B19 is a small DNA virus. Infection with parvovirus B19 during pregnancy may cause serious complications in the fetus, including hydrops fetalis and fetal death. The purpose of the present study is to clarify the clinical manifestations and outcomes of parvovirus B19 infection during pregnancy. This prospective study enrolled 478 women with suspected B19 infections during pregnancy between 1999 and 2004. One hundred cases (21%) of B19 infection were detected in 478 pregnant women who had been exposed to B19. Serological infection was confirmed by measurement of B19-specific IgM and IgG in sera. Forty-nine cases reported maternal clinical symptoms and 51 cases were asymptomatic. Facial rash was the most common symptom, with 51% (25/49) of the symptomatic patients complaining of either a facial, body or limb rash. The most common infectious source was children living in the home. Overall, the incidence of adverse fetal effects (including hydrops fetalis and fetal death) related to intrauterine B19 infection was 7% (7/100), and all seven cases were exposed to B19 infection before 20 weeks of gestation. Although half of the cases with parvovirus B19 infections during pregnancy were asymptomatic, patients with adverse fetal effects tended to be symptomatic including rash and fever. These clinical data may supply useful information to produce clinical guidelines for managing B19 infection during pregnancy.