Cannabis for Endometriosis Pain: Promising but Inconclusive

Mar 12, 2026

Cannabis-Based Treatments Show Potential for Endometriosis Pain, but Evidence Remains Observational

Key Points

Highlights:

Cannabis-based medicinal products were associated with reduced pain and improved health-related quality of life in women with endometriosis-associated chronic pain.
However, because the evidence comes from observational studies without a control group, the findings should be interpreted cautiously and causality cannot be established.

Importance:

Chronic pelvic pain remains difficult to manage in many women with endometriosis.
Observational evidence suggesting potential benefits of cannabis-based therapies highlights the need for well-designed randomized controlled trials to determine efficacy and safety.

What’s done here:

This is a prospective observational cohort study evaluating patient-reported outcomes after initiation of cannabis-based medicinal products in women with endometriosis-associated chronic pain.
Sixty-three patients were followed longitudinally, with assessments performed at baseline and at 1, 3, 6, 12, and 18 months after treatment initiation.
Outcomes included validated measures of pain severity, health-related quality of life (EQ-5D-5L), anxiety, and sleep quality, together with documentation of adverse events and treatment tolerability.

Key results:

The initiation of cannabis-based medicinal products was associated with improvements in multiple patient-reported pain outcomes over the 18-month follow-up period.
The EQ-5D-5L quality-of-life index value improved at all follow-up time points compared with baseline.
Measures of anxiety and sleep quality also improved during the study period.
Clinically meaningful improvements were observed in Brief Pain Inventory scores and visual analogue scale pain severity measures.
Adverse events were reported in 25.4% of patients, most of which were non-serious.

Strengths and Limitations:

Strengths are the prospective design, the use of validated patient-reported outcome measures, and the longitudinal follow-up of patients for up to 18 months after treatment initiation.
Limitations are the relatively small sample size, the observational design without a control group, and the possibility of confounding from concomitant therapies or expectancy effects, which prevent causal inference.
Because the study lacked a control group, a causal relationship between cannabis-based treatment and symptom improvement cannot be established.

From the Editor-in-Chief – EndoNews

"Chronic pelvic pain associated with endometriosis remains one of the most challenging aspects of disease management. Despite advances in hormonal therapy and surgical techniques, a substantial proportion of patients continue to experience persistent or recurrent pain. This therapeutic gap has driven increasing interest in alternative and adjunctive approaches, including cannabinoid-based treatments.

The current study contributes to this evolving discussion by examining patient-reported outcomes in women with endometriosis-associated chronic pain after initiation of cannabis-based medicinal products. The reported improvements in pain scores, health-related quality of life, anxiety, and sleep parameters are noteworthy, particularly given the longitudinal follow-up extending to 18 months. These observations align with broader literature suggesting that cannabinoids may influence pain perception through modulation of the endocannabinoid system, which is known to interact with inflammatory, neural, and central pain-processing pathways.

However, the findings must be interpreted within the methodological constraints of the study design. Without a control group or randomization, improvements observed over time cannot be definitively attributed to the treatment itself. Chronic pain conditions are characterized by fluctuating symptom patterns, and patient-reported outcomes may be influenced by expectancy effects, concurrent therapies, or natural variation in disease activity. In addition, the relatively small cohort limits the ability to fully characterize safety signals and heterogeneity of response.

Importantly, this study should be viewed as hypothesis-generating rather than practice-changing. It highlights a potential area of therapeutic interest while underscoring the need for rigorously designed randomized controlled trials that evaluate efficacy, optimal dosing, safety, and long-term outcomes in patients with endometriosis-associated pain."

As the understanding of endometriosis increasingly incorporates neuroinflammatory and central sensitization mechanisms, the exploration of therapies targeting neural signaling pathways may become an important component of future research. Whether cannabinoid-based therapies will ultimately have a defined role in endometriosis pain management remains uncertain, but carefully conducted clinical trials will be essential to determine their place within evidence-based care.

Lay Summary

Cannabis-based medicinal products may be associated with improvements in pain and health-related quality of life in women with endometriosis-associated chronic pain, according to a new study published in the Australian and New Zealand Journal of Obstetrics and Gynaecology. However, because the findings come from an observational study without a control group, the results cannot establish that cannabis directly caused these improvements.

To explore this potential association, researchers led by Dr. Sodergren from the Medical Cannabis Research Group and Imperial College London, and Curaleaf Clinic, London, UK, the United Kingdom levaluated patient-reported outcomes in 63 women with endometriosis-associated chronic pain who initiated treatment with cannabis-based medicinal products.

Participants were followed prospectively, and patient-reported outcome measures were assessed at baseline and at 1, 3, 6, 12, and 18 months after treatment initiation. The investigators also recorded adverse events during follow-up.

The results showed that the initiation of cannabis-based therapy was associated with improvements in several pain-related outcomes over time. Scores on the Brief Pain Inventory (BPI) and pain severity visual analogue scale showed clinically meaningful improvements during follow-up.

Measures of health-related quality of life also improved. The EQ-5D-5L index, a standardized measure of general health status, increased compared with baseline across all follow-up time points. Improvements were also reported in anxiety and sleep quality scores.

Adverse events were reported by 25.4% of patients, with the most common symptoms including dry mouth, nausea, fatigue, and concentration difficulties.

Because the study lacked a control group and used an observational design, the authors caution that a cause-and-effect relationship cannot be established. Randomized controlled trials will be necessary to determine whether cannabis-based treatments are truly effective for managing endometriosis-associated chronic pain.