Prenatal management of 746 pregnancies at risk for congenital toxoplasmosis.

When infection with Toxoplasma gondii occurs during pregnancy, there is a risk that the parasite will cause severe congenital toxoplasmosis. We developed a method of diagnosing and treating congenital toxoplasmosis in utero. Diagnosis was based on the identification of maternal acute infection, followed by culture of fetal blood and amniotic fluid, testing of fetal blood for toxoplasma-specific IgM and nonspecific measures of infection, and ultrasound examination of the fetal brain. Treatment included the administration of antibiotics to all mothers with confirmed acute infection during pregnancy, with more intensive antibiotic treatment of those who had infected fetuses and who chose to continue the pregnancy. We report a prospective study of 746 documented cases of maternal toxoplasma infection, in which the infants were followed for at least three months. Infection was diagnosed antenatally in 39 of 42 fetuses. Twenty-four of the 39 pregnancies were terminated, and 15 were continued. All the mothers were treated with spiramycin throughout pregnancy; if fetal infection was demonstrated, pyrimethamine and either sulfadoxine or sulfadiazine were added to the regimen. Of the 15 fetuses with congenital toxoplasmosis who were carried to term, all but 2, who had chorioretinitis, remained clinically well during follow-up. We conclude that prenatal diagnosis of congenital toxoplasmosis is practical and that prenatal therapy in women who wish to continue their pregnancies reduces the severity of the manifestations of the disease.