Maternal and Congenital Toxoplasmosis: Diagnosis and Treatment Recommendations of a French Multidisciplinary Working Group

Abstract

Women infected with toxoplasmosis during pregnancy do not present symptoms in most cases, but the consequences of the congenital infection may be severe for the unborn child. Fetal damage can range from asymptomatic to severe neurological alterations to retinal lesions prone to potential flare up and relapses lifelong. Despite the possible severity of outcome, congenital toxoplasmosis (CT) is a neglected disease. There is no consensus regarding screening during pregnancy, prenatal/postnatal treatment or short or medium term follow-up. Since 1992, France has offered systematic serological testing to non-immune pregnant women, monthly until delivery. Any maternal infection is thus detected; moreover, diagnosis of congenital infection can be made at birth and follow-up can be provided. “Guidelines” drawn up by a multidisciplinary group are presented here, concerning treatment, before and after birth. The recommendations are based on the regular analysis of the literature and the results of the working group. The evaluation of the recommendations takes into account the robustness of the recommendation and the quality of the evidence.

Fifteen-minute consultation: Management of the infant born to a mother with toxoplasmosis in pregnancy

“…A positive T. gondii- specific IgM result during pregnancy suggests acute T. gondii infection, probably acquired after conception, and an associated risk of transplacental transmission. Previous maternal specimens, such as booking bloods, should be retrospectively tested; however, there are important caveats to interpretation, summarised in table 1 6 7 9–11. In equivocal cases, further testing should be undertaken either locally or at a national reference laboratory 6…”

“…Comparing serial blood results may demonstrate increasing antibody titres (IgM and/or IgG dye test) or confirm seroconversion during pregnancy (table 1). 6 7 9–12 If infection acquired before conception can be confirmed, the risk to the pregnancy from T. gondii is considered low (in immunocompetent women), that is, T. gondii- specific IgG positive, IgM negative, with or without high IgG avidity on booking or preconception bloods.…”

“…9 In infected infants treated before, at or soon after birth, a serological response may not occur until treatment is withdrawn. Thus, negative serological findings in such cases cannot exclude congenital infection, and follow-up testing is required after completion of treatment 11…”

“…Ocular disease, such as chorioretinitis and scarring identified on specialist review, may be the only manifestation of CT, with no other visible clinical findings 15 18. Since these lesions can be delayed, developing later in childhood, repeat ophthalmological assessments should be considered beyond infancy to an age when the child is able to identify significant visual changes (and potentially lifelong) 6 7 11 12…”

“…The underlying rationale is that newborns with untreated symptomatic CT have a significant risk of developing severe long-term complications, including intellectual, neurological, visual and hearing deficits. Untreated infants with subclinical infection can have similar outcomes, although the risk remains uncertain 7 11 12 19…”