The Vaginal Microbiome as a Tool to Predict rASRM Stage of Disease in Endometriosis: a Pilot Study Original paper
Researched by:
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Kimberly Eyer
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Kimberly Eyer
Kimberly Eyer, a Registered Nurse with 30 years of nursing experience across diverse settings, including Home Health, ICU, Operating Room Nursing, and Research. Her roles have encompassed Operating Room Nurse, RN First Assistant, and Acting Director of a Same Day Surgery Center. Her specialty areas include Adult Cardiac Surgery, Congenital Cardiac Surgery, Vascular Surgery, and Neurosurgery.
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Women’s Health
Women’s Health
Women’s health, a vital aspect of medical science, encompasses various conditions unique to women’s physiological makeup. Historically, women were often excluded from clinical research, leading to a gap in understanding the intricacies of women’s health needs. However, recent advancements have highlighted the significant role that the microbiome plays in these conditions, offering new insights and potential therapies. MicrobiomeSignatures.com is at the forefront of exploring the microbiome signature of each of these conditions to unravel the etiology of these diseases and develop targeted microbiome therapies.
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Endometriosis
Endometriosis
Endometriosis involves ectopic endometrial tissue causing pain and infertility. Validated and Promising Interventions include Hyperbaric Oxygen Therapy (HBOT), Low Nickel Diet, and Metronidazole therapy.
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Kimberly Eyer
Researched by:
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Kimberly Eyer
ID
Kimberly Eyer
Microbiome Signatures identifies and validates condition-specific microbiome shifts and interventions to accelerate clinical translation. Our multidisciplinary team supports clinicians, researchers, and innovators in turning microbiome science into actionable medicine.
Karen Pendergrass
What Was Studied?
This study investigated the potential use of the vaginal microbiome as a diagnostic tool to predict the stage of disease severity in endometriosis, based on the revised American Society for Reproductive Medicine (rASRM) staging system. Conducted as an observational cross-sectional pilot study, researchers characterized the gut and vaginal microbiome profiles of women with and without endometriosis to explore non-invasive biomarkers for disease staging. A total of 59 women participated, 35 with endometriosis and 24 controls. Rectal and vaginal samples were collected at two different points in the menstrual cycle—the menstrual and follicular phases—to assess the microbial composition’s correlation with rASRM stages. Illumina sequencing was utilized to analyze 16S rRNA gene amplicons, with community state types (CSTs) assigned to classify the vaginal microbiota. Random forest-based machine-learning models were constructed to evaluate the predictive power of vaginal microbiota profiles during different menstrual phases.
Who Was Studied?
The study included 35 women with a confirmed diagnosis of endometriosis and 24 control subjects without the disease. Participants were recruited from the University of Sao Paulo and the Massachusetts Institute of Technology, with all subjects providing written informed consent. Inclusion criteria required histological confirmation of endometriosis, while controls were women undergoing laparoscopic surgery for other benign gynecological conditions. Key exclusion criteria included recent antibiotic or hormone use, active infections, autoimmune diseases, and any history of sexually transmitted infections. The vaginal and rectal samples were collected during both the follicular and menstrual phases, known to influence microbial community dynamics.
What Were the Most Important Findings?
The study revealed that the vaginal microbiome’s composition significantly differed between endometriosis patients and controls, particularly during the menstrual phase. Classification models built from vaginal microbial profiles during menstruation accurately predicted rASRM stage 1–2 versus stage 3–4 endometriosis. The genus Anaerococcus emerged as the top predictive operational taxonomic unit (OTU) for distinguishing between early and advanced stages of the disease. Notably, the transition of community state types (CSTs) also reflected disease severity. During the menstrual phase, there was a marked increase in CST IV (characterized by anaerobic bacteria dominance) among both endometriosis patients (30%) and controls (25%), with a simultaneous loss of CST II and CST V. CST I, typically dominated by Lactobacillus crispatus, appeared more prevalent in endometriosis patients during menstruation, suggesting an immunomodulatory role that may contribute to the disease’s local inflammatory environment. These microbial changes were consistent with differences in local immune response and hormonal fluctuations. This pilot study is the first to demonstrate that vaginal microbiome profiles, particularly the presence of Anaerococcus, may serve as a non-invasive biomarker for endometriosis staging, potentially offering a diagnostic tool that bypasses the need for invasive surgical confirmation.
| Microbial Group | Endometriosis Findings | Clinical Implications |
|---|---|---|
| Anaerococcus | Increased in rASRM stages III–IV | Marker for advanced disease severity |
| CST IV (Community State Type) | Dominant during menstruation | Associated with low Lactobacillus and high microbial diversity |
| Lactobacillus spp. | Decreased during menstrual phase | Reduced protective barrier; potential inflammation driver |
| Machine Learning Prediction | High accuracy (AUC = 0.89) | Potential for non-invasive staging of endometriosis |
| Vaginal Microbiome Shifts | Correlated with menstrual cycle phase | Indicates dynamic microbial changes tied to inflammation |
What Are the Greatest Implications of This Study?
The findings from this study suggest that the vaginal microbiome, specifically the composition of community state types and the presence of Anaerococcus, may be harnessed as a non-invasive biomarker to predict the stage of endometriosis severity. This has profound implications for clinical practice, as it could reduce the dependency on invasive laparoscopy for disease staging, which is currently the gold standard. If validated in larger cohorts, this approach could facilitate early detection and better stratification of endometriosis patients, enabling more targeted and personalized therapeutic interventions. Furthermore, the study underscores the significance of microbiome-driven inflammation in the pathophysiology of endometriosis, opening avenues for microbiome-targeted therapies as a novel strategy to mitigate disease progression and symptom severity. The integration of vaginal microbiome profiling into clinical diagnostics could revolutionize the early detection and management of endometriosis, addressing a critical unmet need in gynecological health.
Endometriosis
Endometriosis involves ectopic endometrial tissue causing pain and infertility. Validated and Promising Interventions include Hyperbaric Oxygen Therapy (HBOT), Low Nickel Diet, and Metronidazole therapy.