Characterization of Gut and Tongue Coating Microbiota in Patients With Diminished Ovarian Reserve

Dysbiosis of Gut-Tongue Coating Microbiota Crosstalk and Its Clinical Association With Diminished Ovarian Reserve: A Microbiome-Based Case-Control Study

The goal of this observational study is to investigate the distinct tongue manifestation characteristics in patients with diminished ovarian reserve (DOR) compared to healthy individuals, and to clarify the features of tongue coating microbiota, gut microbiota, and their interrelationships in DOR patients. The main question it aims to answer is:

Whether there are significant differences in tongue manifestations, tongue coating microbiota, and gut microbiota characteristics between DOR patients and healthy populations; Whether associations exist between tongue coating microbiota and gut microbiota in DOR patients; Whether the pathogenesis of DOR may influence estrogen metabolism through alterations in oral and gut microbiota.

This study enrolled DOR patients and healthy women as controls to systematically analyze compositional differences in intestinal and tongue coating microbiota between the two groups. Using 16S rDNA sequencing technology combined with bioinformatics methods, we screened characteristic microbiota associated with DOR and identified microbial markers significantly correlated with serum estrogen levels (AMH, FSH) through Spearman correlation analysis. We further compared abundance differences of homologous bacteria between tongue coating and gut microbiota to determine whether DOR alters the abundance or prevalence of specific bacterial species by affecting tongue-gut axis microbial interactions. The potential of tongue-gut differential microbiota combinations as non-invasive diagnostic biomarkers for DOR was explored.

Inclusion Criteria Developed in accordance with:

The 13th Five-Year Plan textbook Obstetrics and Gynecology (9th Edition) by China National Health Commission The 14th Five-Year Plan National Key Publication Reproductive Endocrinology (2nd Edition) Expert Consensus on Clinical Diagnosis and Treatment of Diminished Ovarian Reserve (2022)

Inclusion Criteria:

• Female patients aged >20 years.
• Diagnosis required meeting the essential criterion of AMH <1.1 ng/mL plus at least one supportive criterion: FSH >10 IU/L, FSH/LH ratio >3.0, or AFC <5-7 follicles (measured on menstrual days 2-3).
• Conscious with intact cognitive/linguistic functions to comply with study protocols.
• Approved by Ethics Committee of Hangzhou TCM Hospital Affiliated to Zhejiang Chinese Medical University, with written informed consent obtained.

Exclusion Criteria:

• Female participants aged <20 years.
• Women in menopause, pregnancy, or lactation period.
• Participants with comorbidities that may interfere with drug efficacy (e.g., severe chronic diseases).
• Severe primary disorders involving cardiovascular, hepatic, renal, hematopoietic systems, or psychiatric illnesses.
• Non-compliance with medication protocols during the study, or cases with undeterminable efficacy outcomes/incomplete data.
• Use of sex hormone therapy within the past 3 months.
• Diagnosis of reproductive system malignancies.
• Gastrointestinal disorders or abnormal liver function.
• Poor adherence to study protocols or lost to follow-up.