A Scoping Systematic Review of Cannabis Use in Endometriosis

Endometriosis, affecting 6%-10% of reproductive-age women, causes chronic pelvic pain, dysmenorrhea, and infertility. Current treatments have limitations and consequently there is rising interest in effects of cannabis on pain and inflammation associated with endometriosis.

This scoping review primarily aimed to characterise the effects of cannabis on endometriosis-associated pain and detail the reported adverse events.

A search was collected on PubMed, MEDLINE (Ovid), and EMBASE (Ovid) databases on 16th January 2024. Studies were included if they were in-human or clinical studies evaluating the effects of cannabis in endometriosis in non-pregnant adults.

Thirteen studies, including 4 ongoing studies, were included. All nine completed studies, with 1,787 participants, were cross-sectional. Pain (57.3%-95.5%) was the most common indication for cannabis use, followed by sleep and gastrointestinal distress (15.2%-78.5%). Cannabis was most commonly inhaled (51.6%-80.3%) or ingested (25%-76.9%). Eight (61.5%) studies asked about participants' perception of the efficacy of cannabis. These utilised a range of methods preventing pooling of results. However, most reported improvement in at least a proportion of their studied population. Adverse events were reported by 10.2% to 52.0% of patients, with the most common being "feeling high" (euphoria) and a dry mouth.

Several observational studies have reported that cannabis helped to reduce endometriosis-associated pain. However, there is a paucity of high-quality prospective longitudinal data and randomised controlled trials to evaluate the safety profile an efficacy of medical cannabis in endometriosis-associated pain. These provide support, alongside existing pre-clinical data, for the importance of further assessment in randomised controlled trials.