[Toxoplasmosis in pregnancy. Prevention, diagnosis, and therapy].

Toxoplasmosis is a worldwide health problem. Infection of a pregnant woman can result in severe fetal morbidity or in subclinical neonatal infection; most subclinical cases will develop ocular and neurological sequelae. Fetal infection and clinical outcome is related to when in pregnancy toxoplasmosis was acquired. The risk of transmission increases from 14% in the first trimester to 29% in the second and 59% in the third. Conversely, clinical damage decreases from about 80% in the first to 10% in the third trimester, but up to 50% of patients with subclinical congenital toxoplasmosis will develop neurologic and ocular sequelae. Congenital toxoplasmosis can be prevented by identification of non immune women at the beginning of pregnancy, by giving information on how to avoid the infection and by a serological follow-up until the delivery. Serological follow-up is based on repeated testing for specific IgG and IgM, but other serologic methods are necessary to differentiate between acute and chronic infections and possibly on a single serum sample. Procedures to detect fetal infection are ultrasound examination, cordocentesis and amniocentesis; prenatal diagnosis relies on demonstration of toxoplasma in fetal blood or amniotic fluid by mouse inoculation. Very promising results have recently obtained by the PCR-method applied to amniotic fluid samples. All strongly suspected cases of acquired toxoplasmosis in pregnancy have to be treated.