Keywords
Human microbiome
Vaginal smear
Infertility
Female infertility
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Abstract
Objective: To gather the most recent evidence from the literature on the relationship between vaginal microbiota and female infertility, highlighting the main pathophysiological mechanisms and possible therapies. Literature review: The vaginal microbiota plays a central role in maintaining local homeostasis and protecting against genital pathogens, preventing infections and imbalances in this environment. Alterations in this ecosystem, known as dysbiosis, have been associated with adverse reproductive outcomes, including infertility and failures in assisted reproductive technologies. Current findings indicate that vaginal microbiota profiles with low dominance of lactobacilli and the presence of specific anaerobic bacteria may compromise fertility. The use of probiotics, targeted antimicrobial therapies, and personalized microbiota modulation strategies, which represent promising interventions, is also discussed. Final considerations: It is considered that integrating vaginal microbiota assessment into reproductive clinical practice can not only broaden the understanding of the etiology of infertility, but also point to new diagnostic, prognostic, and therapeutic possibilities.
References
BAQUERO F e NOMBELA C. The microbiome as a human organ. Clin Microbiol Infect. 2012; 18(4): 2-4.
BAUD D, et al. Genital microbiota in infertile couples. Reprod Biomed Online. 2025; 51(5): 105056.
BERG G, et al. Microbiome definition re-visited: old concepts and new challenges. Microbiome. 2020; 8(1): 103.
BERNABEU A, et al. Effect of the vaginal microbiome on the pregnancy rate in women receiving assisted reproductive treatment. J Assist Reprod Genet. 2019; 36(10): 2111–2119.
CAMPBELL M, et al. Synthesis without meta-analysis (SWiM) in systematic reviews: reporting guideline. BMJ. 2020; 368: 6890.
CHEN PC, et al. Differences in Vaginal Microbiota Composition Between Infertile and Fertile Patients: A Prospective Study. Diagnostics (Basel). 2025; 15(19): 2544.
CHEN X, et al. Vaginal microbiota alterations under supraphysiological estradiol state during in vitro fertilization-embryo transfer (IVF-ET) and the association with reproductive outcomes. BMC Microbiol. 2025; 25(1).
CHOPRA C, et al. Role of vaginal microbiota in idiopathic infertility: a prospective study. Microbes Infect. 2024; 26(4): 105308.
COCOMAZZI G, et al. Refining Unfavorable Vaginal Microbial Community in Infertile Women Subjected to Precision Probiotic Intervention: An Exploratory Single-Arm, Prospective, Open-Label, Interventional Study. Microorganisms. 2025; 13(3): 547.
DI PIETRO M, et al. HPV/Chlamydia trachomatis co-infection: metagenomic analysis of cervical microbiota in asymptomatic women. New Microbiol. 2018; 41(1): 34–41.
ESKEW AM, et al. Association of vaginal bacterial communities and reproductive outcomes with prophylactic antibiotic exposure in a subfertile population undergoing in vitro fertilization: a prospective exploratory study. F&S Sci. 2021; 2(1): 71–79.
FERNÁNDEZ L, et al. Application of Ligilactobacillus salivarius CECT5713 to achieve term pregnancies in women with repetitive abortion or infertility of unknown origin by microbiological and immunological modulation of the vaginal ecosystem. Nutrients. 2021; 13(1): 162.
FILARDO S, et al. Diversity of cervical microbiota in asymptomatic Chlamydia trachomatis genital infection: a pilot study. Front Cell Infect Microbiol. 2017; 7: 256.
HAAHR T, et al. Vaginal microbiota and in vitro fertilization outcomes: development of a simple diagnostic tool to predict patients at risk of a poor reproductive outcome. J Infect Dis. 2019; 219(11): 1809–1817.
HASAN Z, et al. An insight into the vaginal microbiome of infertile women in Bangladesh using metagenomic approach. Front Cell Infect Microbiol. 2024; 14: 1390088.
HUERGA LÓPEZ C, et al. L. Ligilactobacillus salivarius CECT5713 Increases Term Pregnancies in Women with Infertility of Unknown Origin: A Randomized, Triple-Blind, Placebo-Controlled Trial. Nutrients. 2025; 17(11): 1860.
HUGERTH LW, et al. Defining Vaginal Community Dynamics: daily microbiome transitions, the role of menstruation, bacteriophages, and bacterial genes. Microbiome. 2024; 12(1): 153.
KOEDOODER R, et al. The ReceptIVFity cohort study protocol to validate the urogenital microbiome as predictor for IVF or IVF/ICSI outcome. Reprod Health. 2018; 15(1): 202.
KOEDOODER R, et al. The vaginal microbiome as a predictor for outcome of in vitro fertilization with or without intracytoplasmic sperm injection: a prospective study. Hum Reprod. 2019; 34(6): 1042–1054.
KUNASETH J, et al. Vaginal microbiome of women with adenomyosis: a case-control study. PLoS One. 2022; 17(2): 263283.
LOKKEN EM, et al. A prospective preconception cohort study of the association between Mycoplasma genitalium and fecundability in Kenyan women trying to conceive. Hum Reprod. 2023; 38(10): 2020–2027.
MASTROMARINO P, et al. Effects of vaginal lactobacilli in Chlamydia trachomatis infection. Int J Med Microbiol. 2014; 304(5-6): 654-661.
MELGAÇO ACC, et al. Potential of maintaining a healthy vaginal environment by two Lactobacillus strains isolated from cocoa fermentation. Biomed Res Int. 2018; 7571954.
MORENO I, et al. Evidence that the endometrial microbiota has an effect on implantation success or failure. Am J Obstet Gynecol. 2016; 215(6): 684–703.
NARDINI P, et al. Lactobacillus crispatus inhibits the infectivity of Chlamydia trachomatis elementary bodies: an in vitro study. Sci Rep. 2016; 6: 29024.
NUGENT RP, et al. Reliability of diagnosing bacterial vaginosis is improved by a standardized method of gram stain interpretation. J Clin Microbiol. 1991; 29(2): 297–301.
RIGANELLI L, et al. Structural variations of vaginal and endometrial microbiota: hints on female infertility. Front Cell Infect Microbiol. 2020; 10: 350.
SANTANA ASA e PÓVOA AM. Female genital tract microbiome: the influence of probiotics on assisted reproduction. Rev Bras Ginecol Obstet. 2024; 46.
SCHENK M, et al. Effect of probiotics on vaginal Ureaplasma parvum in women suffering from unexplained infertility. Reprod Biomed Online. 2021; 43(3): 503–514.
SESSA R, et al. Effect of bovine lactoferrin on Chlamydia trachomatis infection and inflammation. Biochem Cell Biol. 2017; 95(1): 34-40.
SINGER M, et al. The profiling of microbiota in vaginal swab samples using 16S rRNA gene sequencing and IS-pro analysis. BMC Microbiol. 2021; 21(1): 100.
SOUZA SV, et al. Vaginal microbioma and the presence of Lactobacillus spp. as interferences in female fertility: A review system. JBRA Assist Reprod. 2023; 27(3): 496-506.
THANABOONYAWAT I, et al. Pregnancy outcomes after vaginal probiotic supplementation before frozen embryo transfer: a randomized controlled study. Sci Rep. 2023; 13(1): 11892.
TIAN Q, et al. Assessing vaginal microbiome through Vaginal Microecology Evaluation System as a predictor for in vitro fertilization outcomes: a retrospective study. Front Endocrinol (Lausanne). 2024; 15: 9.
VAINAMO S, et al. Longitudinal analysis of vaginal microbiota during IVF fresh embryo transfer and in early pregnancy. Microbiol Spectr. 2023; 11(6): 165023.
VAN DEN TWEEL MM, et al. The Vaginal Microbiome Changes During Various Fertility Treatments. Reprod Sci. 2024; 31(6): 1593-1600.
VAN HAREN A, et al. ProVag: the effect of oral probiotics on the vaginal microbiota composition in women receiving medical assisted reproduction in a Dutch fertility clinic - protocol of a randomised, placebo-controlled, double-blind study. BMJ Open. 2025; 15(7): 96959.
YUAN X, et al. Vaginal microbiome and recurrent pregnancy loss. Infect Immun. 2025; 93(8): 5325.