Background: Infections caused by Toxoplasma gondii (T. gondii), HIV, and rubella virus are major causes of adverse pregnancy outcomes in sub-Saharan Africa. Data from Gabon remain limited. This study aimed to determine the simultaneous seroprevalence of these pathogens among pregnant women in Owendo, Gabon.

Methods: A prospective descriptive study was conducted from October 2022 to May 2024 at the Owendo University Teaching Hospital. Pregnant women in their first trimester were screened for HIV (Vidas® Duo Ultra HIV5) and for T. gondii and rubella IgG/ IgM antibodies (Vidas® bioMérieux ELFA). Sociodemographic data and serological results were analysed using Statview 5.0, with significance set at p < 0.05.

Results: Among 1,705 participants (median age 25 [20–31] years), HIV prevalence was 3.45% (46/1,334), mainly in women aged 25–35 years (p=0.003). T. gondii IgG seroprevalence was 63.5% (658/1,036), while IgM positivity was 1.9% (18/927). Rubella IgG antibodies were detected in 85.7% (786/917), with 2.3% (21/917) IgM positivity. Combined immunity to both Toxoplasma and Rubella was observed in 53.2% (475/893), whereas 6.7% (60/893) were non-immune.

Conclusion: More than one-third of pregnant women in Owendo remain susceptible to at least one major congenital infection. These findings highlight the need for integrated antenatal screening, improved vaccination coverage, and targeted health education to reduce preventable perinatal morbidity and mortality in Central Africa.