Maternal and clinical predictors of congenital toxoplasmosis: A prospective cohort study in Brazil

OBJECTIVE: Congenital toxoplasmosis (CT) remains a major global health concern, with particularly high incidence in Latin America. Despite its relevance, prospective data from Brazilian cohorts are scarce. METHODS: We conducted a prospective cohort study at the Instituto de Puericultura e Pediatria Martagão Gesteira (IPPMG/UFRJ), Rio de Janeiro, including 55 pregnant women with confirmed Toxoplasma gondii infection and their infants (January 2022-April 2025). Maternal sociodemographic, obstetric, behavioral, and clinical data were collected prospectively. Infants were classified as infected or exposed based on serological, molecular, radiologic, and clinical criteria. Regression analysis was used to compare the groups. RESULTS: Among 55 mother-infant pairs followed, 11 (20%) infants were diagnosed with CT. No significant associations were observed with maternal sociodemographic or environmental factors. However, mothers of infected infants had diagnosis later during gestation (24.3 vs. 16.4 weeks; P = 0.02), cohort entry later during gestation (31.2 vs. 24.3 weeks; P = 0.02), and more prenatal visits (7.7 vs. 4.9; P = 0.04 visits) (more prenatal visits likely reflecting increased monitoring after diagnosis). Adenomegaly (P = 0.04) and other systemic symptoms (P = 0.05) were more frequent among mothers of infected infants. Neonatal parameters did not differ significantly, but five infected infants presented neuroimaging abnormalities, five had ophthalmologic lesions, and six tested positive for IgM and/or PCR. CONCLUSION: Toxoplasmosis diagnosis later during gestation and symptomatic maternal infection were associated with CT. These findings highlight the need for systematic maternal screening, considering maternal clinical manifestations, timely referral, and close clinical monitoring to prevent vertical transmission and adverse neonatal outcomes.