When
toxoplasmosis is acquired during pregnancy, there is a risk of severe
congenital defect in the foetus. Maternal treatment with
spiramycin limits the transplacental passage of the parasite to the foetus but does not prevent
infection in all cases. Prenatal diagnosis should be based on specific and fast methods to prescribe the more potent combination of
sulfadiazine and
pyrimethamine. This study evaluates PCR in the prenatal diagnosis of
toxoplasmosis; PCR was based on the detection of the gene coding for the P30
surface protein. Amniotic fluid from 44 women with suspected foetal
infection was tested by PCR and results were compared to those of conventional diagnostic tests on foetal blood and amniotic fluid. PCR was positive in 7 out of 10 samples from proven
congenital toxoplasmosis cases. Sensitivity of PCR was similar to cell culture and mouse inoculation of amniotic fluid but was superior to tests carried out on foetal blood (specific
IgM, eosinophil and platelet counts, gamma glutamyl
transferase, mouse inoculation). In two cases, PCR was positive with no detected
infection of the foetus. In this study, the combination of fast detection methods, ie cell culture and PCR of amniotic fluid, eosinophil and platelet counts, GGT activity and specific
IgM, enabled us to confirm 10/10 cases of
congenital toxoplasmosis in less than a week. PCR therefore appears to be an additional test which improves early prenatal diagnosis of
toxoplasmosis.