[Congenital toxoplasmosis. 5 cases of mother-to-child transmission of pre-pregnancy infection].

Five cases of congenital toxoplasmosis consecutive to a maternal toxoplasma infection that had preceded pregnancy were observed. One woman with normal immune system had developed a well-documented lymph node toxoplasmosis 2 months before conceiving. Four women had chronic toxoplasmosis diagnosed in the course of an immunosuppressive disease: Hodgkin's disease in 1 case, systemic lupus erythematosus in 2 cases and pancytopenia in 1 case. Toxoplasmosis had been recognized 3, 5 and 10 years respectively before conception in 3 women, and at an uncertain date in 1 woman. Three women had received corticosteroids during pregnancy, and 2 had undergone splenectomy. Among the 6 children (2 were twins), 1 presented with severe foetal disease at birth, 1 developed lethal systemic toxoplasmosis after birth, 1 showed hydrocephalus with therapeutically well-controlled chorioretinitis, 1 had isolated eye lesion and 2 had asymptomatic infection. The parasite seems to have been transmitted after the 20th week of pregnancy in all cases. The physiopathology of mother-to child toxoplasma transmission, the role played by maternal immunodeficiency and the practical implications of these exceptional cases are discussed.