Medicinal cannabis could provide a new treatment option for those with endometriosis, with a study led by the University of Otago, Wellington showing it reduced pain, improved sleep and lowered anxiety.
Dr Claire Henry
The study, led by Dr Claire Henry from the Department of Surgery and Critical Care, involved 28 people with endometriosis and/or related pelvic pain who were prescribed cannabidiol (CBD) oil alone or in combination with dried cannabis flower for three months.
The participants recorded weekly pain scores on a numerical scale, with 0 being no pain, and 10 being the worst pain imaginable. They also completed an endometriosis health profile questionnaire before the trial started and at the end of the 12 weeks. Seventeen were interviewed about their experiences at the end of the study.
Dr Henry says overall pelvic pain among the group dropped from a level of 5.4 to 3.7, and the level of the worst pain dropped from 7.6 to 5.3. There was a clinically meaningful improvement in their health-related quality of life scores.
The study is the first prospective cohort study of medicinal cannabis for endometriosis-related pain in New Zealand. The findings are published in the international journal BMC Complementary Medicine and Therapies.
Dr Henry says while CBD did not work for everyone, for some the impacts were life changing.
One of those in the study talked of preparing to re-enter the workforce after three years out, while another said they were "in such a good place health wise [they were] starting to try to have a baby".
The benefits on their sleep and anxiety had an almost equal effect on their quality of life as the reduction in pain.
It is estimated that as many as one in nine people assigned female at birth have endometriosis, an inflammatory condition where endometrial-like tissue grows outside the uterus. Symptoms include severe and debilitating menstrual pain, non-cyclical pelvic pain, fatigue and reduced fertility.
Dr Henry says current treatment includes pain management, hormonal medications, and laparoscopic surgery.
"However, medical management of endometriosis is often associated with side effects, and patient satisfaction with these treatments can be limited."
Those in the trial were using personalised combinations of analgesic, contraceptive, and holistic medication as well as lifestyle modifications in an attempt to self manage their pain.
Several of the participants reported previously using opioid-based analgesics, including tramadol, but said they provided limited or inconsistent relief and were often accompanied by undesirable side effects, including nausea, dizziness and fatigue.
There were few side effects reported from CBD use, with participants perceiving it as a gentler alternative that could still offer effective symptom relief.
The research project was supported by funding from endometriosis support group Endo Warriors Aotearoa.
Yessenia Sandoval
The founder, Yessenia Sandoval, says the study highlights the need for accessible, evidence-informed care pathways for endometriosis.
"Those with endometriosis find it really difficult to find medications that work, that are affordable, and that don't come with unmanageable side effects."
Dr Henry says large-scale studies and clinical trials are needed so the safety, efficacy and long-term effect of using medicinal cannabis to treat endometriosis-related pain can be further evaluated.
"In particular, it is important to understand how medicinal cannabis treats pain and for who it would work best.
"Endometriosis pain management is often complex and individualised, and while CDB had benefits in terms of pain relief and improved sleep for many of our participants, we still need to understand how it works and what the long-term effects from its use might be."
Publication details
The research paper, 'Perceived impact of medicinal cannabis on pelvic pain and endometriosis related symptoms in Aotearoa New Zealand: an observational cohort study
