Prenatal education for congenital toxoplasmosis

No. 285-Toxoplasmosis in Pregnancy: Prevention, Screening, and Treatment

BACKGROUND

One of the major consequences of pregnant women becoming infected by Toxoplasma gondii is vertical transmission to the fetus. Although rare, congenital toxoplasmosis can cause severe neurological or ocular disease (leading to blindness), as well as cardiac and cerebral anomalies. Prenatal care must include education about prevention of toxoplasmosis. The low prevalence of the disease in the Canadian population and limitations in diagnosis and therapy limit the effectiveness of screening strategies. Therefore, routine screening is not currently recommended.

OBJECTIVE

To review the prevention, diagnosis, and management of toxoplasmosis in pregnancy.

OUTCOMES

Outcomes evaluated include the effect of screening on diagnosis of congenital toxoplasmosis and the efficacy of prophylaxis and treatment.

EVIDENCE

The Cochrane Library and Medline were searched for articles published in English from 1990 to the present related to toxoplasmosis and pregnancy. Additional articles were identified through references of these articles.

VALUES

The quality of evidence is rated and recommendations made according to guidelines developed by the Canadian Task Force on Preventive Health Care (Table 1).

BENEFITS, HARMS, AND COSTS

Guideline implementation should assist the practitioner in developing an approach to screening for and treatment of toxoplasmosis in pregnancy. Patients will benefit from appropriate management of this condition.

SPONSOR

The Society of Obstetricians and Gynaecologists of Canada.

RECOMMENDATIONS

Prenatal education for congenital toxoplasmosis

BACKGROUND

Congenital toxoplasmosis is considered a rare but potentially severe infection. Prenatal education about congenital toxoplasmosis could be the most efficient and least harmful intervention, yet its effectiveness is uncertain.

OBJECTIVES

To assess the effects of prenatal education for preventing congenital toxoplasmosis.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 May 2015), and reference lists of relevant papers, reviews and websites.

SELECTION CRITERIA

Randomized and quasi-randomized controlled trials of all types of prenatal education on toxoplasmosis infection during pregnancy. Cluster-randomized trials were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy.

MAIN RESULTS

Two cluster-randomized controlled trials (RCTs) (involving a total of 5455 women) met the inclusion criteria. The two included trials measured the effectiveness of the intervention in different ways, which meant that meta-analysis of the results was not possible. The overall quality of the two studies, as assessed using the GRADE approach, was low, with high risk of detection and attrition bias in both included trials.One trial (432 women enrolled) conducted in Canada was judged of low methodological quality. This trial did not report on any of the review's pre-specified primary outcomes and the secondary outcomes reported results only as P values. Moreover, losses to follow-up were high (34%, 147 out of 432 women initially enrolled). The authors concluded that prenatal education can effectively change pregnant women's behavior as it increased pet, personal and food hygiene. The second trial conducted in France was also judged of low methodological quality. Losses to follow-up were also high (44.5%, 2233 out of 5023 women initially enrolled) and differential (40% in the intervention group and 52% in the control group). The authors concluded that prenatal education for congenital toxoplasmoses has a significant effect on improving women's knowledge, whereas it has no effect on changing women's behavior. In this trial 17/3949 pregnant women seroconverted for toxoplasmosis: 13/2591 (0.5%) in the intervention group and 4/1358 (0.3%) in the control group. The rate of seroconversion detected during the study did not differ between groups (risk ratio (RR) 1.70, 95% confidence interval (CI) 0.56 to 5.21; participants = 3949; studies = one, low quality evidence). The number of events was too small to reach conclusions about the effect of prenatal education on seroconversion rate during pregnancy.No other randomized trials on the effect of prenatal education on congenital toxoplasmosis rate, or toxoplasmosis seroconversion rate during pregnancy were detected.

AUTHORS' CONCLUSIONS

Even though primary prevention of congenital toxoplasmosis is considered a desirable intervention, given the lack of related risks compared to secondary and tertiary prevention, its effectiveness has not been adequately evaluated. There is very little evidence from RCTs that prenatal education is effective in reducing congenital toxoplasmosis even though evidence from observational studies suggests it is. Given the lack of good evidence supporting prenatal education for congenital toxoplasmosis prevention, further RCTs are needed to confirm any potential benefits and to further quantify the impact of different sets of educational intervention.

Prenatal education for congenital toxoplasmosis

BACKGROUND

Congenital toxoplasmosis is considered a rare but potentially severe infection. Prenatal education about congenital toxoplasmosis could be the most efficient and least harmful intervention, yet its effectiveness is uncertain.

OBJECTIVES

To assess the effects of prenatal education for preventing congenital toxoplasmosis.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (15 January 2012), PubMed (1966 to 15 January 2012), EMBASE (1980 to 15 January 2012), CINAHL (1982 to 15 January 2012), LILACS (1982 to 15 January 2012), IMEMR (1984 to 15 January 2012), and reference lists of relevant papers, reviews and websites.

SELECTION CRITERIA

Randomized and quasi-randomized controlled trials (RCTs) of all types of prenatal education on toxoplasmosis infection during pregnancy. Cluster-randomized trials were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and study quality. Two review authors extracted data. Data were checked for accuracy.

MAIN RESULTS

Two cluster-randomized controlled trials (involving a total of 5455 women) met the inclusion criteria. The two included trials measured the effectiveness of the intervention in different ways which meant that meta-analysis of the results was not possible One trial (432 women enrolled) conducted in Canada was judged of low methodological quality. The authors did not report measure of association but only provided P values (P less than 0.05) for all outcomes. Moreover, losses to follow-up were high (34%, 147 out of 432 women initially enrolled). The authors concluded that prenatal education can effectively change pregnant women's behavior as it increased pet, personal and food hygiene. The second trial conducted in France was also judged of low methodological quality. Losses to follow-up were high (44.5%, 2233 out of 5023 women initially enrolled) and differential (40% in the intervention group and 52% in the control group). The authors concluded that prenatal education for congenital toxoplasmoses has a significant effect on improving women's knowledge whereas it has no effect on changing women's behavior. In this trial 17/3949 pregnant women seroconverted for toxoplasmosis: 13/2591 (0.5%) in the intervention group and 4/1358 (0.3%) in the control group. The number of events was too small to reach conclusions about the effect of prenatal education on seroconversion rate during pregnancy.No other randomized trials on the effect of prenatal education on congenital toxoplasmosis rate, or toxoplasmosis seroconversion rate during pregnancy were detected.

AUTHORS' CONCLUSIONS

Even though primary prevention of congenital toxoplasmosis is considered a desirable intervention, given the lack of related risks compared to secondary and tertiary prevention, its effectiveness has not been adequately evaluated. There is very little evidence from RCTs that prenatal education is effective in reducing congenital toxoplasmosis even though evidence from observational studies suggests it is. Given the lack of good evidence supporting prenatal education for congenital toxoplasmosis prevention, further RCTs are needed to confirm any potential benefits and to further quantify the impact of different sets of educational intervention.

Lack of awareness of risk factors for primary toxoplasmosis in pregnancy

BACKGROUND

The overall seroprevalence of toxoplasma antibodies in women of childbearing age in Ireland is 25% [1]. Hence, 75% of women remain susceptible to primary toxoplasma infection during pregnancy, which if transmitted to the foetus can cause ocular, neurological and other sequelae. Toxoplasma exposure during pregnancy can be avoided if there is an awareness of the potential sources of infection, mainly contaminated food, water, soil and cat faeces.

AIMS

To determine risk factor exposure in a cohort of women with congenitally infected infants and to assess maternal risk awareness prior to diagnosis of infection.

METHODS

Data, prospectively gathered during 2 years of pilot newborn screening for congenital toxoplasmosis in Ireland, was retrospectively analysed. Known risk factors for acquisition of infection were identified. Women were questioned regarding risk awareness and implementation of avoidance measures, if any, during pregnancy.

RESULTS

Fifteen congenitally infected infants were identified by newborn screening. Seventy-three percent of their mothers (11/15) reported lack of knowledge concerning risk factors for toxoplasma infection or its potential threat to the foetus. Ingestion of raw or undercooked meat during pregnancy was the predominant source of toxoplasma cyst exposure identified. Contact with cats was reported in just one case.

CONCLUSIONS

Most women were uneducated about the risks posed by Toxoplasma gondii exposure during pregnancy. There is a clear need for better educational programmes regarding primary prevention of congenital toxoplasmosis if neonatal infection is to be avoided.

Congenital toxoplasmosis--a report on the Danish neonatal screening programme 1999-2007

OBJECTIVES

This paper reports on the national neonatal screening programme for congenital toxoplasmosis (CT) in Denmark conducted from 1999 to 2007, including background, basis for initiation of screening, methods, results, and finally reasons for the discontinuation of the screening.

METHODS

A nationwide screening was conducted at Statens Serum Institut, including >98% newborns, and using filter paper eluates (Guthrie card, PKU card) obtained from newborns 5-10 days old. These were analysed for Toxoplasma gondii-specific antibodies (IgM), and if positive, then IgM (ISAGA). Confirmatory serology was performed on children and their mothers (IgM, IgG, IgA, dye test) where infection was suspected, and children with suspected or confirmed CT initiated a 3-month treatment regimen with pyrimethamine, sulfadiazine and folinic acid supplements. Selective cohorts were followed with regard to developmental and clinical outcome.

RESULTS

A total of 100 children were diagnosed with CT in the screening period, and only 2 cases were detected outside of the screening programme. CT prevalence was 1.6 per 10,000 live-born infants. Follow-up studies showed new retinochoroidal lesions in affected children despite treatment.

CONCLUSION

Screening was terminated August 2007, after it became apparent that no benefit of treatment could be shown. CT was evaluated using a Danish adaptation of the Uniform Screening Panel (ACMG), showing CT as an unlikely candidate for screening today. Whereas results might be comparable with other low-endemic countries with similar strains of T. gondii, neonatal screening and treatment might offer different results in regions with either high prevalence or different strains of T. gondii.

[Eye and pregnancy.]

Pregnancy may cause ocular changes, for example refractive changes or contact lens intolerance. A number of ocular diseases may deteriorate. Especially preexisting diabetic retinopathy may worsen. Vaginal delivery is nearly always possible. Caesarean section is not required due to myopia, peripheral retinal degenerations or after retinal surgery. Most topically applied drugs usually used in ophthalmology are safe during pregnancy.