The Role of Probiotics in the Treatment of Endometriosis (ProMetrioS): a Randomised Double-blinded Placebo-controlled Cross-over Trial
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- The protocol lists: Omni Biotic Stress, Placebo.
- Who it may be relevant to
- Registry conditions: Endometriosis, Probiotics. Basic parameters: up to 35 years · Female.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- Croatia
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
Unsure about the terms? Read our patient guide →
Overview
ProMetrioS is a randomised blinded placebo-controlled cross-over trial investigating the effect of specific multistrain probiotics in patients with endometriosis. The aim of this clinical trial is to determine whether probiotic treatment can significantly modulate gut microbiome composition and functionality in endometriosis patients, specifically parameters associated with the estrobolome.
Detailed description
Patients will be recruited among the outpatient population of the National Center for Endometriosis, Department of Gynecological Surgery and Urology, Gynecology Department, University Hospital Center Zagreb following the inclusion and exclusion criteria.
To participate in the study all patients will be required to sign the Informed Consent form.
All patients will undergo a complete anamnesis via a digital form to investigate their lifestyle (occupation, stress, diet, physical activity level).
The study period will be 6 months: eight weeks on either option (verum/placebo), with an eight week washout period in between. The purpose of the washout period is to allow the gut microbiome to return to baseline. The washout period was determined based on previous gut microbiota studies with a similar design (reference), based on the fact that the gut microbiota can change rapidly (\< 7 days) r.
The outcome measures (gut microbiome, quality of life) will be assessed in four distinct time points in context of the planned intervention.
T1 - before the intervention (start-of-study)
T2 - after the first intervention cycle/phase 1 (verum/placebo) of two months
T3 - after the wash-out phase of two months
T4 - after the second intervention cycle/phase 2 (verum/placebo) of two months (end-of-study)
Stool sampling will be performed with the aid of specific kits indepently by the patients. Lifestyle and quality of life will be evaluated by an online form designed specifically for the purpose of this study in Microsoft Office Forms (Microsoft, San Francisco, USA), short Online Form.
Through the process of randomization, patients will be allocated to either first receive the verum (probiotic) or the placebo (maltodextrin), and second the placebo or verum inversely.
Both patients and researchers involved will be blinded (double-blind study), the patients will be informed that they are going to take a probiotic twice for two months with a two-month time division. The intervention will consist of treatment with a multistrain probiotic formulation (Omni Biotic Stress) and the placebo which is identical in all its characteristics and packaging. Patients will be instructed to consume one sachet a day of each (probiotic) for 8 weeks and to report any symptoms or side effects related to its use. Adherence control will be carried out through the patient's notes on a separate online form provided, and also by checking the number of sachets used.
Since this is a cross-over study, data will be compared between time-points T1 and T2, and time-points T3 and T4, with the goal of minimizing the potential effect if we find that the effect of the probiotics lasted longer than eight weeks in those randomized into the intervention arm first.
Interventions
- Dietary supplement Omni Biotic Stress
Multistrain probiotic formulation (Omni Biotic Stress), 1 sachet daily for 8 weeks - Other Placebo
Inert powder identical in appearance and taste to probiotic, 1 sachet daily for 8 weeks
Primary outcome measures
- Change in relative abundance of gut microbial taxa and functional pathways related to the estrobolome in fecal samples [Time frame: At baseline, after 8 weeks (end of phase 1), and after 24 weeks (end of phase 2)]
Secondary outcome measures (2)
- Change in quality of life measured by EHP-5 questionnaire [Time frame: Week 1, Week 8, Week 16, Week 24 (6 months)]
- Change in quality of life measured by SEQOL questionnaire [Time frame: Week 1, Week 8, Week 16, Week 24 (6 months)]
Eligibility criteria
Minimum Age: - Maximum Age: 35 Years Sex: Female Gender Based: Ye - only women can participate in this study Accepts Healthy Volunteers: No
Inclusion criteria
- adult subjects with stage III or IV endometriosis diagnosis confirmed by biopsy
Exclusion criteria
- Age > 35 years
- Immunocompromised patients
- Patients with chronic inflammatory diseases (e.g., autoimmune disorders)
- Pregnancy
- Use of supplements and foods with probiotics
- Use of immunosuppressant, antibiotic, proton pump inhibitors and corticosteroid drugs
- Use of probiotics product less than one month before start of study or during study
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: No
Study design
- Allocation
- Randomized
- Model
- Crossover
- Masking
- Double blind
- Primary purpose
- Treatment
Study locations
Croatia · 1 center
- University Hospital Center Zagreb — Zagreb
Publications
- Kralj S, Zeman K, Mikus M, Karacic A, Prso AL, Coric M, Renko I. The role of probiotics in the treatment of endometriosis (ProMetrioS): a randomized double-blinded placebo-controlled cross-over trial. Trials. 2026 Feb 20;27(1):242. doi: 10.1186/s13063-025-09405-5. PMID 41715206
Identifiers
NCT: NCT06929364 · ProMetrioS2024