An interventional study of Monoplace Hyperbaric Chamber (Class III medical device) in Endometriosis-related Pain, sponsored by Sunnybrook Health Sciences Centre. Recruiting at 1 site in Canada. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-04-15.
Sponsored by Sunnybrook Health Sciences Centre · Not applicable, Interventional, and Treatment
Endometriosis, is a condition where tissue from the uterus, called endometrium, grows outside of the uterus. This effects up to 10% of women, and can lead to long-lasting, moderate to severe pelvic pain, infertility and other symptoms. This can affect a woman's quality of life (including increased risk of depression and anxiety) and is associated with increased healthcare costs.
Current treatments are often limited by serious side effects, and many women resort to surgery. Surgery is also associated with complications and there are long wait times for procedures, sometimes over 3 years. This means that many women continue to suffer from symptoms while they wait for surgery. Therefore, new effective treatments for endometriosis pain are needed.
New research suggests that inflammation and stress caused by lack of oxygen in the affected areas may cause endometriosis. Hyperbaric Oxygen Therapy (HBOT), where patients are placed in a small chamber with higher than normal levels of oxygen, suppresses inflammation and promotes tissue healing. Because inflammation is central to this condition, HBOT has emerged as a potential treatment.
In this study, the investigators will test if HBOT, in addition to the standard treatments, is more effective at treating endometriosis pain than the standard treatments alone.
Endometriosis is caused when endometrial-like tissue is found outside of the uterus. It predominantly affects women of reproductive age, with an estimated prevalence of 10% worldwide. Chronic pain related to endometriosis is one of the primary manifestations that lead individuals to seek treatment, with many women reporting moderate to severe pain that can have serious consequences for mental health and quality of life.
Current therapeutic approaches for endometriosis include hormonal therapies (e.g. oral contraceptive pills, progestins, and Gonadotropin-Releasing Hormone agonists/antagonists). While these treatments may provide temporary symptom relief, they are often associated with serious side effects and preclude conception during treatment. The efficacy of other medical interventions remains controversial, therefore surgical procedures are often indicated. However, surgery also has associated risks, has long wait times (between 6 months and 3 years), and a considerable percentage of patients experience recurrence of pain following surgical resection.
Pathologically, endometriosis is characterized by angiogenesis, inflammation, and a chronic hypoxic state at the cellular level. Because of this, Hyperbaric Oxygen Therapy (HBOT), which suppresses inflammation and promotes tissue healing, offers promise as a novel therapeutic modality. This is supported by murine models, which demonstrate the ability of HBOT to reduce inflammation and inflammatory cytokines in the context of endometriosis in animals. However, there have not been any human studies investigating the use of HBOT for treatment of endometriosis and related pain.
This study aims to explore HBOT as a treatment for endometriosis related pelvic pain. Specifically, the investigators will test if HBOT, in addition to the standard treatments (e.g. hormonal and non-hormonal medical options), is more effective at treating endometriosis pain than the standard treatments alone.
901 studies on the registry are indexed under Endometriosis; 259 are open to participants now.
This study's planned enrollment of 64 is close to the median of 64 across 525 interventional studies indexed under Endometriosis.
Browse Endometriosis studies →Sunnybrook Health Sciences Centre is the lead sponsor of 566 studies on the registry; 134 are open to participants now.
Of its 6 completed or terminated interventional studies of FDA-regulated products, 2 (33%) have results posted.
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Exclusion Criteria:
Standard multi-modal therapy
Standard multi-modal therapy + 40 HBOT treatments (2 ATM for 90 mins daily, 5 days a week)
Device: Monoplace Hyperbaric Chamber (Class III medical device)
Participants in the intervention group will be triaged to the closest hyperbaric facility to their address and treated with 40 HBOTs (2 ATM for 90 mins, scheduled daily from Monday to Friday). As HBOT is not a service currently offered at Sunnybrook Hospital, all HBOT treatments will be provided at three collaborating outpatient facilities, Halton Hyperbaric Unit, Restore Hyperbaric Oxygen \& Medical Centre (CPSO-certified Level-II OHP), and Rouge Valley Hyperbaric Medical Centre. All three facilities have the exact same hyperbaric chambers, run by anesthesiologists with advanced training, thus treatments will be identical at all sites.
Change in pain symptoms on the NRS
Assessed on the numeric rating scale between 0 to 10, with 10 indicating the worst possible pain
Time frame: At baseline, weekly for the first 8 weeks after enrollment, then at 3/4/5/6 month follow ups
Change in pain frequency
The change in pain frequency will be assessed on a 5-point Likert scale, where 1 is "never" and 5 is "always."
Time frame: At baseline, weekly for the first 8 weeks after enrollment, then at 3/4/5/6 month follow ups
Change in opioid consumption
Collected as a categorical variable ("Are you taking 1) more, 2) same or 3) less compared to start of treatment?")
Time frame: At baseline, weekly for the first 8 weeks after enrollment, then at 3/4/5/6 months
Participant Quality of Life on the EHP-30
The Endometriosis Health Profile-30 is a validated, high-sensitivity, 30-item endometriosis-specific assessment tool for capturing the impact of endometriosis on patient's lives.
Time frame: At baseline, and every month for 6 months
Participant Quality of Life on the SF-36
The Quality of Life Short Form Survey-36 is a widely used tool to assess an individual's overall health-related quality of life.
Time frame: At baseline, and every month for 6 months
Adherence to HBOT protocol
How many patients complete protocol (minimum 4 treatments per week with \>35 treatments)
Time frame: At 8 weeks (or last session)
Satisfaction assessed by a Patient Satisfaction Questionnaire
Subjective questionnaire completion at end of treatment inquiring about HBOT experience, barriers to and promoters of treatment
Time frame: At 8 weeks (or last session) and 6 months following enrollment
Cost of study completion
Cost of study completion on a per patient basis including research support, healthcare resource costs, and patient-related personal costs (transport, time from work)
Time frame: Throughout study completion, an average of 6 months
Plan to share: Yes — De-identified participant-level data will be made available upon reasonable request to study PI following publication of full trial results.
Supporting information: Study protocol, Sap, Icf, Csr, Analytic code
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