Association between Toxoplasma gondii infection and diabetes in pregnant women: a systematic review and meta-analysis

Toxoplasma gondii is a globally prevalent zoonotic parasite that can cause significant maternal and neonatal complications during pregnancy. Diabetes mellitus, a condition associated with impaired immune function, may increase susceptibility to such infection. Despite the severe consequences of toxoplasmosis in immunocompromised individuals, no systematic review has previously evaluated its association with diabetes in pregnant women. Following the PRISMA 2020 guidelines, a comprehensive search was conducted across PubMed, Scopus, Web of Science and Google Scholar (updated in August 2025). Eligible human observational studies reporting Toxoplasma gondii infection among pregnant women with gestational diabetes mellitus (GDM), type 1 diabetes, or type 2 diabetes were included. Data extraction and quality assessment were performed using Hoy et al.’s tool and Newcastle–Ottawa Scale. Meta-analysis was conducted using Stata version 17. Out of 198 retrieved articles, 9 studies (7 case–control and 2 cross-sectional) met the inclusion criteria. In cross-sectional studies, pooled IgG seroprevalence among diabetic pregnant women was 29% (95% CI: 0.22–0.35), with low heterogeneity (I² = 23.63%). IgM seroprevalence was 7% (95% CI: 0.02–0.12). Case–control meta-analysis revealed a significant association between IgG seropositivity and diabetic pregnancy (OR = 2.07, 95% CI: 1.66–2.58; p < 0.001) without evidence of publication bias or heterogeneity. IgM seropositivity was not significantly different between diabetic and healthy pregnant women (OR = 1.81, 95% CI: 0.97–3.35; p > 0.05). Diabetic pregnant women exhibit a significantly higher prevalence of chronic T. gondii infection (IgG) compared to non-diabetic controls, highlighting a potential association that warrants further investigation. However, the association with acute infection remains unclear. More prospective, geographically diverse studies are needed to clarify causality, underlying mechanisms, and clinical outcomes.