[Prevention of congenital toxoplasmosis].
Toxoplasma gondii can be transmitted from mother to fetus during primary maternal infection acquired after or, possibly, slightly before conception. The incidence of congenital infection is highest in the third trimester, while severity is greatest when maternal infection is acquired during the first trimester. About 50 per cent of mothers who acquire the infection during gestation, if not treated, will give birth to infected infants. Incidence of congenital toxoplasmosis varies from 0.5 to 6.5 cases per 1000 live births. Serologic screening before or very early in pregnancy is required to identify seronegative women who are at risk to acquire the infection during pregnancy. Prevention of congenital toxoplasmosis is obtained by educating pregnant women at risk about how to prevent the infection and by diagnosing acute infection of mother. Every mother who demonstrates seroconversion for toxoplasmosis during pregnancy has to be treated as soon as possible. Therapy is based on spiramycin that achieves high concentrations in the placenta; if the fetus is infected pyrimethamine plus sulphonamides are administered since fourth month. Chemotherapy of the infected pregnant mother reduces the incidence of congenital toxoplasmosis and the severity of the disease in the newborn. Intrauterine infection can be detected by fetal blood sampling, by amniocentesis and ultrasound examination; prenatal diagnosis is mandatory if an abortion is being considered.