THE ROLE OF THE ENDOMETRIAL MICROBIOME IN INFERTILITY AND REPRODUCTIVE HEALTH: CURRENT EVIDENCE AND FUTURE DIRECTIONS

Klaudia Dybalska; Mateusz Kęska; Michael Platschek; Anna Barbara Tuleja; Michał Drabik; Julia Kosmulska; Maksym Sikora; Sylwia Wiktoria Kolano; Jakub Nowak; Karol Józef Szkarłat

doi:10.31435/ijitss.4(48).2025.4242

Authors

Klaudia Dybalska Brzeziny Specialist Hospital, Brzeziny, Poland https://orcid.org/0009-0006-9900-0167
Mateusz Kęska 5th Military Clinical Hospital with Polyclinic SPZOZ, Kraków, Poland https://orcid.org/0000-0003-0712-7613
Michael Platschek Blessed Marta Wiecka Hospital in Bochnia, Bochnia, Poland https://orcid.org/0009-0008-9085-4531
Anna Barbara Tuleja University Hospital in Wroclaw (USK), Wrocław, Poland https://orcid.org/0009-0003-9185-9493
Michał Drabik 5th Military Clinical Hospital with Polyclinic SPZOZ, Kraków, Poland https://orcid.org/0009-0004-0198-4926
Julia Kosmulska University Hospital in Wroclaw (USK), Wrocław, Poland https://orcid.org/0009-0000-8770-3793
Maksym Sikora Hospital of the Brothers Hospitallers of St. John of God in Kraków, Kraków, Poland https://orcid.org/0009-0008-4495-7732
Sylwia Wiktoria Kolano Independent Public Healthcare Institution of the Ministry of the Interior and Administration in Kraków, Kraków, Poland https://orcid.org/0009-0000-1180-1135
Jakub Nowak Independent Public Healthcare Institution of the Ministry of the Interior and Administration in Kraków, Kraków, Poland https://orcid.org/0009-0003-7097-0635
Karol Józef Szkarłat Medical University of Silesia in Katowice, Faculty of Medical Sciences in Katowice, Katowice, Poland https://orcid.org/0009-0004-2889-8382

DOI:

https://doi.org/10.31435/ijitss.4(48).2025.4242

Keywords:

Uterine Microbiome, Vaginal Microbiota, Implantation, Infertility

Abstract

Infertility affects 10–12% of couples and growing evidence implicates the reproductive tract microbiome in implantation success. This narrative review synthesizes human studies on the vaginal and uterine (endometrial) microbiota in relation to fertility outcomes and mechanistic markers. We searched PubMed/MEDLINE, Embase, and Scopus (2000–30 Oct 2025) for randomized and observational studies reporting implantation, clinical pregnancy, live birth, or relevant biomarkers (e.g., α/β-diversity, inflammatory cytokines, LIF). Data were summarized descriptively due to heterogeneity in sampling, sequencing pipelines, and outcome definitions. Across studies, the uterine cavity is no longer viewed as sterile and typically shows low-biomass, often Lactobacillus-lean communities distinct from the vagina. Dysbiosis—frequently characterized by reduced Lactobacillus dominance and increased anaerobes—has been associated with lower implantation and clinical pregnancy rates and with inflammatory profiles that may suppress LIF. Limited interventional data suggest that targeted therapies (e.g., probiotics or antibiotics followed by probiotics) can restore eubiosis in some patients and may improve implantation, but evidence remains preliminary and at risk of bias. We conclude that microbiome composition is plausibly linked to implantation and early pregnancy outcomes, yet clinical adoption is premature. Standardized sampling, rigorous contamination control, multi-omic profiling, and well-powered randomized trials are needed to define actionable thresholds and therapeutic strategies.

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