Toxoplasmosis and pregnancy: the prevention of congenital toxoplasmosis.

Programs to prevent congenital toxoplasmosis based on the evaluation of serologic tests can be performed at three periods: 1. before pregnancy (serologic, epidemiologic screening of "at risk" women); 2. during pregnancy (detection by seroconversion); 3. at delivery (diagnosis of evident or latent congenital infection). The screening devices, the IHA, IFA, and IgM-IFA tests, should be performed first and after 3 weeks possibly repeated. During pregnancy the observation of seroconversion or, in any case, an increase in serologic titer at the second blood withdrawal and, at delivery, high serologic titers are signs of fetal risk. The significance of the data has furthermore to be evaluated by specific IgM quantification on pure serologic fractions and by in vivo isolation of Toxoplasma gondii from amniotic fluid, placenta, or the newborn CSF, blood, and/or tissue. This data may suggest the necessity of therapeutic termination of pregnancy or application of a specific chemoprophylaxis/chemotherapy.