Antenatal diagnosis of congenital toxoplasmosis: evaluation of the biological parameters in a cohort of 286 patients

Objective To evaluate the biological parameters obtained by cordocentesis and amniocentesis in the antenatal diagnosis of congenital toxoplasmosis. Design Nine-year retrospective study. Setting Parasitology Laboratory, Department of Obstetrics and Gynaecology and Department of Paediatrics, Centre Hospitalo-Universitaire, Montpellier, France. Participants Two hundred and eighty-six pregnant women infected with toxoplasmosis between 7 and 34 weeks of gestation. Methods Detection of abnormalities by ultrasound examination. Detection in fetal blood of Toxoplasma, of specific IgM and IgA and of nonspecific biological markers. Detection in amniotic fluid of Toxoplasma. Results Out of 286 antenatal diagnoses, 211 were negative (1st group), 40 were positive (2nd group) and led to 8 medical abortions, and 35 were uncertain (3rd group). In the 1st and 3rd groups respectively, 7 (3.3 %) and 5 (14.3 %) cases of congenital toxoplasmosis were observed. Overall, 52 cases of congenital toxoplasmosis were detected : 12 were clinically apparent, 36 subclinical (of which 12 were in groups 1 and 3) and 4 were lost to follow up. Conclusion There is substantial importance in making the diagnosis of toxoplasmosis antenatally in order to limit the number of medical abortions. In our series, the most accurate predictor was the detection of the fetal antibody response (specific IgM and IgA) to Toxoplasma.