Estimating the national seroprevalence of infection in pregnant women, France 2021.

Toxoplasmosis during pregnancy can cause congenital malformations and fetal death. This study aimed to estimate the seroprevalence among pregnant women participating in the 2021 French national perinatal survey and identify associated factors. All women giving birth in France during the study period were invited to participate. Data collected included demographic information, nationality, socio-economic status, education level, and serological status. Women were classified as seropositive if IgG antibodies were present or if seroconversion occurred during pregnancy. Univariate and multivariate Poisson regression analyses with robust error variance were used to estimate prevalence ratios and identify factors associated with seropositivity. Among 12,612 women, the overall seroprevalence was 25.9%, and 0.22% seroconverted during pregnancy. Seroprevalence increased by 5% with every 5-year age increment and was significantly higher in the French overseas territories of Mayotte (75.0%), La Réunion (35.8%), and French Guiana (33.3%). Seroprevalence was also higher among women with lower educational levels (47.4% for primary education) and those of Sub-Saharan African nationality (52.0%). Geographic and socio-demographic variations may reflect dietary and environmental diversity. Despite declining seroprevalence in France, continued public health efforts, particularly among high-risk populations, remain critical to minimize the impact of congenital toxoplasmosis.