Congenital toxoplasmosis: systematic review of evidence of efficacy in treatment in pregnancy

Objectives

To assess whether or not treating toxoplasmosis in pregnancy reduces the risk of congenital toxoplasmosis infection.

Methods

We planned to assess all randomised studies comparing at least two groups of pregnant women with evidence of recent toxoplasma infection, one group of which received no antibiotic treatment. Relevant reports of less robust experimental studies in which there were (non randomly allocated) control groups were also inspected. Studies comparing two different antibiotic treatment were excluded. An electronic search was performed using the key words "congenital and toxoplasmosis" of the following databases: MEDLINE (1966-2000), Embase (1989-2000), Pascal (1990-2000), Biological Abstracts (1993-2000), Pharmaceutical abstracts (1970-2000), Current contents (1998-2000) and the Cochrane controlled trial register. There were also contacts with experts in the field including those in the European Research Network on Congenital Toxoplasmosis. Reports of possible eligible studies were scrutinised by two investigators. The quality of the studies was assessed in relation to (i) the criteria for diagnosing maternal infection, and (ii) the study design, using a predefined scale based on six equally weighted items (randomised group allocation, recruitment at the same location for both groups, recruitment during the same period, for both groups, analysed based on the intention to treat, inclusion in the analysis of patients lost to follow-up before analysis, no loss to follow-up or proportion < 10 % of the total samples).

Results

Out of 3500 papers reviewed, no randomised controlled trial was identified. Eleven non randomised studies met our predefined criteria compared treated pregnant women to non treated ones Controle groups were generally non directly comparable to treated groups. Age of gestation at maternal infection was taken into account in one study only. Congenital toxoplasmosis was common in treated groups. Five studies showed that treatment was effective and six that it was not.

Conclusions

It is still unclear whether antenatal treatment in women with presumed toxoplasmosis reduces congenital toxoplasmosis transmission of Toxoplasma gondii. Effects of treatment need to be evaluated before a decision can be made regarding the overall utility of a prenatal screening.

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