Infection by parvovirus B 19 during pregnancy: a review.

Fetal infection by Parvovirus B 19 is a common cause of fetal anemia and nonimmune hydrops fetalis and may result in fetal death. Recent improvements in diagnosing parvovirus infections by sensitive molecular biology techniques now allow for a new insight into its pathogenic rule, immunology, and the varied clinical manifestations. The estimated overall risk of fetal loss after maternal exposure is about 6.5 percent, which is much less than previously thought. Inasmuch as complete spontaneous reversal of fetal hydrops has been commonly described, controversy exists regarding the management of the fetus with clinical signs of infection by Parvovirus B 19. According to the experience that has accumulated, it seems that only cases with severe fetal anemia or signs of fetal compromise should be managed by intrauterine transfusion. This procedure, however, is not without risk. Although an association between fetal viral infection and structural abnormalities has been described, it has not been proved yet. However, infection by Parvovirus B 19 has been recently proposed as a causative factor for congenital red blood cell aplasia.