A Systematic Review of the Prevalence of Endometriosis in Trans Men

OBJECTIVE: This systematic review aims to synthesize available evidence on the prevalence of endometriosis in the trans male population. DATA SOURCES: A systematic review search was conducted using five databases: MEDLINE (OVID), EMBASE, Cochrane Library, Web of Science (via Clarivate), and CINAHL Complete (EBSCO), which were searched between January 2000 and February 2024. METHODS OF STUDY SELECTION: Studies were eligible for inclusion if they: (1) included transgender, transsexual, or trans male individuals as the study population; (2) included participants reporting one or more of the following conditions: endometriosis, pelvic pain, or dysmenorrhoea; (3) were published in a peer-reviewed journal in English between 1 January 2000 and 1 February 2024. Abstracts were screened and reviewed for relevance. Reviewers independently assessed the full-text articles. Data was extracted from the full-text articles using the data extraction tool, Covidence systematic review software 2024. The risk of bias was evaluated using the Risk Of Bias In Non-randomized Studies of Interventions tool. TABULATION, INTEGRATION, AND RESULTS: Of 90 articles screened, 13 were included comprising 1,597 trans men, with a mean age of 26.7 years (SD: 8.1 years). The pooled prevalence of endometriosis was 8.9% (126/1423, 95%CI: 7.4-10.5%). Seven of the studies reported specifically on surgical diagnosis of endometriosis, with a similar prevalence noted in this subset of participants of 9.2%; (50/543; 95% CI: 7.1-11.9%). Those diagnosed with endometriosis were found to have stage 1 disease in 40% of cases (10/25). Non-menstrual pelvic pain was reported by 580 of 1076 participants (53.9%; 95%CI: 50.9-56.9%), dyspareunia by 221 of 566 (39.0%; 95%CI: 35.0-43.2%), dysmenorrhea by 106 of 383 (27.7%; 95%CI: 23.0-32.0%), and abnormal uterine bleeding by 181 of 818 (22.1%; 95%CI: 19.0-25.0%). Testosterone use was reported in 926 of 1,413 participants (65.5%; 95%CI: 63.0-68.0%), with a mean treatment duration of 2.4 years (SD: 1.1 years). CONCLUSION: This systematic review determined a prevalence of endometriosis of 8.9% in the trans male population. Notably, both the low volume of data and potential for bias in studies based on surgical presentation are limitations. There is a high rate of pelvic pain reported among trans male participants, with 53.9% reporting non-menstrual pelvic pain.