Association between the risk of congenital toxoplasmosis and the classification of toxoplasmosis in pregnant women and prenatal treatment in Brazil, 1994-2009.

OBJECTIVES: The objectives of this study were to analyze the association between the classification of toxoplasmosis in the pregnant woman (TP) according to the classification of Lebech et al. and the incidence of congenital toxoplasmosis (CT), also taking into consideration prenatal treatment.

METHODS: A clinical cohort study of 524 children followed-up until 1 year of age was conducted. Adjusted odds ratios (OR) were estimated by logistic regression.

RESULTS: Of 519 pregnant women, 61.3% were not classified due to the incompleteness of hospital records. Among the pregnant women classified as confirmed cases of TP (n=19), the CT risk was six times greater than in the probable/possible group. No case of CT was identified in the group of pregnant women classified as unlikely to have TP. The children with no prenatal treatment (46.2% n=242/524) presented a risk almost three times greater of CT than the treated children (OR 2.77, 95% confidence interval (CI) 1.54-4.97; p=0.001). Complete prenatal treatment was identified as a protecting factor for CT (OR 0.35, 95% CI 0.19-0.65; p=0.001).

CONCLUSIONS: A lack or incomplete prenatal treatment was identified as an important risk factor for CT in this study. The proportions of non-classified mothers and children with no prenatal treatment reflect the need to improve prenatal care in Brazil.