Correlation between bacterial vaginosis and the presence of antisperm antibodies in women experiencing unexplained infertility: a cross-sectional study

Introduction: Bacterial vaginosis (BV) and antisperm antibodies (ASA) are recognised contributors to infertility, yet their combined involvement in unexplained infertility remains insufficiently documented. Their combined influence on unexplained infertility (UI) remains inadequately documented. This study aimed to examine the relationship between BV, its associated pathogens, and ASA in women with UI in Kisangani, Democratic Republic of Congo. Methods A cross-sectional analytical study was conducted from August to November 2023 among 523 infertile couples who had completed the standard investigations. One hundred and forty-four women met the criteria for UI. ASA were detected using a rapid diagnostic test, followed by an indirect mixed antiglobulin reaction test when positive. BV was diagnosed using Nugent scoring. Vaginal pathogens were identified with the VITEK 2 Compact system. Associations were evaluated using the chi-square test, Phi coefficient, and logistic regression models. Results In the full infertile cohort, bacterial vaginosis was significantly linked to ASA positivity (p < 0.001, Phi = 0.383). This association was stronger among women with UI (p < 0.001, Phi = 0.879). In multivariable analysis, ASA were independently associated with Atopobium vaginae (aOR 15.08 [3.30-68.89]), Gardnerella vaginalis (aOR 6.31 [2.09–19.08]), Mobiluncus species (aOR 3.24 [1.07–9.82]), Mycoplasma hominis (aOR 3.60 [1.11–11.68]), and Prevotella timonensis (aOR 3.88 [1.28–11.74]). Conclusion BV and several of its core pathogens show strong associations with ASA in women with UI. These findings support an infection-immune pathway that may contribute to infertility and emphasise the importance of combining microbiological and immunological tests in infertility assessments, highlighting the need for longitudinal studies to clarify temporal relationships.