Transplacental transmission of human parvovirus B19 (B19 virus) to the fetus is an important cause of intrauterine death, abortion, stillbirth, and nonimmune hydrops fetalis. Adverse outcome of pregnancy can occur after symptomatic and asymptomatic maternal infection. Only rare cases of congenital malformations and fetal disease in live-born infants have been associated with intrauterine B19 virus infection. Laboratory results obtained from paired maternal and fetal cord blood samples indicate that a reliable diagnosis of fetal B19 virus infection should be based on detection of parvovirus B19 DNA.