Parvovirus B19 infection in a twin pregnancy.

Background: Parvovirus infection has been associated with the development of nonimmune hydrops fetalis in pregnancy. This report describes a twin pregnancy in which one fetus was affected by parvovirus B19 and the other was not.

Methods: A 35-year-old woman was found to have a twin gestation at genetic amniocentesis. Subsequent ultrasound at 18 weeks showed that twin B had evidence of hydrops fetalis. Serum from the mother tested positive for parvovirus B19 immunoglobulin (Ig) G and IgM. Cultured amniotic fluid from twin B was subsequently found to be positive for parvovirus B19. At 20 weeks' gestation, the hydropic fetus died. The unaffected fetus grew normally. At 40 weeks, the unaffected fetus was delivered vaginally with no difficulties. Cord blood from the unaffected fetus was negative for parvovirus B19 IgM.

Conclusions: This case demonstrates differential infection of parvovirus B19 in a diamniotic, dichorionic twin pregnancy. One twin developed signs of hydrops fetalis consistent with parvovirus B19. The diagnosis was confirmed immunologically and by amniotic fluid culture. The second twin had no evidence of parvovirus B19 and no immunologic suggestion of infection at birth. This is the only known report of such differential transmission of parvovirus B19 in a twin pregnancy.