A case of maternal generalized edema with hyponatremia, hypoosmolality
and secondary hyperaldosteronism was associated with pseudomolar plas
ma human chorionic gonadotropin (hCG) concentrations in a case of feta
l and placental hydrops due to parvovirus B19 infection. Digoxigenin i
n situ hybridization techniques were effective in demonstrating parvov
irus B19 infection on fixed tissues. Hydropic changes in the placenta
may have massively increased the maternal plasma hCG concentration wit
h subsequent fluid imbalance leading to maternal hydrops mimicking mol
ar pregnancy.