Pathologic examination of the placenta in human cases of toxoplasmosis

One hundred sixty one placentae were examined grossly and microscopically, 131 specimens belonged to seropositive patients and 30 specimens belonged to seronegative patients and used as control. 63.3% of the placentae of seropositive patients were macroscopically normal, 9% were hydropic, 21% were of mixed or partially hydropic pattern, 6% had areas of infarction & 0.7% showed areas of calcifications. The most consistent microscopic finding was focal low grade chronic villitis with mononuclear inflammatory infiltrate. In hydropic placentae villous edema was of very variable degree from one placenta to another and from one area to another in the same placenta. Nucleated red blood cells were demonstrated in villous capillaries. The patients had Rh positive factor in their blood.