Exploratory Clinical Study on the Efficacy and Safety of Lactobacillus Johnsonii in the Treatment of Patients with Premature Ovarian Insufficiency

Inclusion Criteria: 1. Age between 20 and 39 years; 2. Irregular menstruation or amenorrhea for \> 4 months; 3. At least two serum baseline follicle-stimulating hormone (FSH) levels \> 25 IU/L (with an interval of more than 4 weeks between measurements); 4. Willing to voluntarily participate in this study, sign the informed consent form, and comply with the investigation and follow-up; 5. Not having participated in other clinical trials within the past 3 months. Exclusion Criteria: 1. Use of antibiotics or probiotics, prebiotics, and live bacterial preparations within the past month or during the intervention period; 2. Received hormone replacement therapy within the past 2 months; 3. Chromosomal abnormalities and genetic defects; 4. Iatrogenic premature ovarian insufficiency; 5. Stage IV endometriosis; 6. Uncontrolled endocrine diseases or autoimmune diseases; 7. Organic gastrointestinal diseases; 8. Infectious diseases of the reproductive, urinary, or digestive systems; 9. Severe cardiovascular, respiratory, renal, hematologic, endocrine, neurological, psychiatric, or other systemic diseases that the investigator believes may interfere with the study evaluation; 10. History of venous thromboembolism; 11. Allergic or intolerant to the components of the investigational probiotic product; 12. Allergic to two or more types of food/medications; 13. Refusal to provide written informed consent; 14. Other conditions deemed unsuitable for participation in the study by the investigator.