Perceived impact of medicinal cannabis on pelvic pain and endometriosis related symptoms in Aotearoa New Zealand: an observational cohort study

Background: Endometriosis, characterised by the growth of endometrial-like tissue outside the uterus, often causes severe pelvic pain, dysmenorrhea, and fatigue. Current medical treatments frequently provide incomplete symptom control and/or significant side effects. Many individuals with endometriosis report symptom improvements with cannabis use, but high-quality evidence remains limited. Methods: A prospective, mixed-methods cohort study was conducted. Participants aged 18–50 years with surgically or clinically diagnosed endometriosis self-engaged with a specialist consultant and were prescribed medicinal cannabis (cannabidiol [CBD] oil alone or in combination with dried cannabis flower). Weekly pain scores, and health-related quality of life (measured by the Endometriosis Health Profile-30 [EHP-30]) were assessed via surveys and standardised questionnaires over three months. Completion interviews were conducted to explore participants’ experiences with medicinal cannabis in greater depth. Results: Participants reported limited adverse events during the study period. Pelvic pain scores decreased over 12 weeks: ‘overall’ pain reduced from 5.46 ± 1.55 (95% CI 0.57) to 3.77 ± 2.25 (95% CI 0.83), and ‘worst’ pain decreased from 7.62 ± 1.51 (95% CI 0.56) to 5.38 ± 2.69 (95% CI 1.00). The mean total EHP-30 score significantly decreased from 68.77 ± 15.17 (95% CI 5.61) to 37.40 ± 16.66 (95% CI 6.17). Qualitative analysis identified four major themes: motivations for seeking medicinal cannabis, experiences of use, barriers to use, and stigma. Conclusions: Medicinal cannabis use was associated with reduction in pain measures and improvements in quality of life among some individuals with endometriosis during this study. Qualitative findings highlighted both perceived benefits and ongoing challenges related to access, dosage and social stigma. These results support the need for larger controlled studies to further evaluate the safety, efficacy, and long-term outcomes of medicinal cannabis as an adjunctive therapy for endometriosis-related pain.