Seroprevalence, Risk Factors and Maternal-Fetal Outcomes of Toxoplasma gondii in Pregnant Women from WHO Eastern Mediterranean Region: Systematic Review and Meta-Analysis

Abstract

Background: The protozoan parasite Toxoplasma gondii may cause serious illness in the immunocompromised. The Toxoplasma gondii seropositive prevalence in pregnant women in WHO Eastern Mediterranean Region countries is inconsistent in the literature and it is associated with outcomes that have not be fully elucidated, hence the need for a better understanding of the pooled seroprevalence and associated maternal and fetal outcomes.

Objective: The objective was to conduct a systematic literature review and determine the pooled prevalence of WHO Eastern Mediterranean Regional countries' pregnant women's seroprevalence of Toxoplasma gondii and the maternal-fetal outcomes.

Methods: This quantitative study examined WHO Eastern Mediterranean countries' maternal-fetal outcomes and Toxoplasma gondii prevalence in pregnant women. The targeted population was pregnant women, while the primary outcome was seropositivity of Toxoplasma gondii, while other outcomes such as maternal and fetal associations and risk factors were determined PubMed, SCOPUS, MEDLINE, and Index Medicus for the Eastern Mediterranean Region (IMEMR) databases were searched up until 30 January 2023. The search terms used were "Toxoplasma gondii" OR "Toxoplasma infection" AND "Pregnant woman" or pregnan* OR Antenatal OR Prenatal OR Gravidity OR Parturition OR Maternal AND WHO Eastern Mediterranean Region). OpenMeta-Analyst and Jamovi were used to analyze the generated data.

Results: In total, 95 of 2947 articles meeting the inclusion criteria examined Toxoplasma gondii prevalence in pregnant women from WHO Eastern Mediterranean countries. The pooled prevalence of Toxoplasma gondii in pregnant women was 36.5% (95%CI: 32.6-40.4) with a median value of 35.64%, range values of 1.38-75.30%, with 99.61% heterogeneity. The pooled seroprevalence of IgG of Toxoplasma gondii was 33.5% (95%CI: 29.8-37.2) with a median value of 33.51%, and a range values of 1.38-69.92%; the pooled seroprevalence of IgM was 3.6% (95%CI: 3.1-4.1)) with a median value of 3.62 and range values of 0.20-17.47%, while cases of pooled seroprevalence of both IgG and IgM positivity was 3.0% (95%CI: 1.9-4.4) with a median value of 2.05 and a range values of 0.05-16.62%. Of the Toxoplasma gondii seropositive women, 1281/3389 (34.8%) 174/1765 (32.9%), 1311/3101 (43.7%), and 715/1683 (40.8%) of them had contact with cats, drank unprocessed milk, ate raw or undercooked meat and ate unwashed raw vegetables, respectively. The maternal-fetal outcomes associated with Toxoplasma gondii seropositivity were a history of abortions, miscarriage, stillbirth, intrauterine fetal death, and premature birth, which were found in 868/2990 (32.5%), 112/300 (36.1%), 111/375 (25.7%), 3/157 (1.9%) and 96/362 (20.1%) of women who tested positive for Toxoplasma gondii antibodies.

Conclusion: The study found a high proportion of Toxoplasma gondii seroprevalence in pregnant women in the WHO Eastern Mediterranean Region, which may be linked to poor outcomes for mothers and their babies. Thus, pregnant women require monitoring and comprehensive prevention strategies for Toxoplasma gondii infection.

Keywords: Eastern Mediterranean; Toxoplasma gondii; miscarriage; pregnancy; stillbirth.

Figure 1

Flowchart of the screening process. Flowchart shows the screening process used, which follows PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) criteria.

Figure 2

Distribution of the included studies by country of study origin. The figure above shows the number of studies found in each of the countries in the WHO Eastern Mediterranean region. The figure shows the number of studies from countries in descending order.

Figure 3

Distribution of the included studies by the method used. The figure shows the number of studies that used various methods to detect the antibodies of Toxoplasma gondii. The figure shows studies based on the method of detection of antibodies in ascending order.

Figure 4

Overall Prevalence of Toxoplasma gondii in pregnant women in WHO Eastern Mediterranean Region. Figure shows the overall estimate of the Toxoplasma gondii seropositive (IgM or IgG positivity). The pooled seropositive prevalence was 36.5% with significant (p < 0.05) heterogeneity of 99.5%. The Ev in the plot means the number of events, while Tr means total numbers.

Figure 5

Funnel plot of the included articles. The figure presents the funnel plot for the included studies. The blank points show the distribution of the studies included and how they are spread from the center of the funnel. The cluster of studies at the top of the funnel shows they have smaller standard errors, while those at the bottom have large standard error. The funnel plot shows a mix of studies of small- and large-size samples.

Figure 6

IgG Toxoplasma gondii Seropositive Prevalence in Pregnant Women in WHO Eastern Mediterranean Region. The figure shows the estimate of the Toxoplasma gondii IgG seropositive, the cumulative independent study IgG seroprevalences. The seropositive prevalence was 33.5% with significant (p < 0.05) heterogeneity of 99.6%. Ev means the number of events, while Tr means the total numbers.

Figure 7

Prevalence of Toxoplasma gondii IgM Seropositive in Pregnant Women in WHO Eastern Mediterranean Region. Figure shows the Toxoplasma gondii IgM seropositivity estimate, which is the cumulative independent study IgM seroprevalence. The seropositive prevalence was 3.6% with significant (p < 0.05) heterogeneity of 95.6%. Ev means the number of events, while Tr means total numbers.

Figure 8

Prevalence of Both IgM and IgG Seropositivity of Toxoplasma gondii in Pregnant Women in WHO Eastern Mediterranean Region. The figure presents the estimate of the Toxoplasma gondii IgG and IgM seropositivity, the cumulative independent study seroprevalence. The seropositive prevalence was 3.0% with significant (p < 0.05) heterogeneity of 93.2%. Ev means number of events, while Tr means total numbers.