Identification of human parvovirus B19 infection in idiopathic nonimmune hydrops fetalis

OBJECTIVE: This retrospective study was designed to determine the incidence of B19 associated with idiopathic nonimmune hydrops fetalis by use of a sensitive molecular tool, the polymerase chain reaction assay. STUDY DESIGN: Placental and fetal tissues from 57 cases of nonimmune hydrops fetalis were analyzed for B19 deoxyribonucleic acid. Thirty-four of these cases were classified as idiopathic. The remaining 23 cases had known, noninfectious-based causes. RESULTS: Eighteen percent of all cases (6/34) of idiopathic nonimmune hydrops fetalis contained B19 deoxyribonucleic acid. In contrast, none of the 23 cases of known, noninfectious-based nonimmune hydrops fetalis examined contained any B19 deoxyribonucleic acid. Presence of the virus was confirmed in each of the six cases by either B19-specific deoxyribonucleic acid in situ hybridization or immunocytochemistry. However, histologic examination was unsuccessful at detecting characteristic viral-like inclusions in one third of the cases. CONCLUSION: Eighteen percent of cases of idiopathic nonimmune hydrops fetalis contained B19 deoxyribonucleic acid. This significant finding demonstrates the usefulness of polymerase chain reaction to aid in the differential diagnosis of this disease. (AM J OBSTET GYNECOL 1996;174:37-42.)