{"paper_id":"dfbe3756-80f6-496b-97b3-177d2e1b176c","body_text":"Adenomyosis is a benign gynecological disorder characterized by aberrant development of endometrial glands and stroma within the myometrium, causing inflammation and neuroangiogenesis. 1 , 2  Adenomyosis often coexists with other gynecological conditions and may cloud the clinical presentation (Appendix 1, available at  www.cmaj.ca/lookup/doi/10.1503/cmaj.201607/tab-related-content ). 1\n\nHistorically thought to affect only older women, adenomyosis is now identifiable on imaging in 30% of women younger than 40 years. 1 , 2  Up to 30% of women with adenomyosis are asymptomatic and symptoms resolve after menopause; asymptomatic or menopausal women do not require management. 1 , 3 , 4\n\nAll women presenting with dysmenorrhea or heavy menstrual bleeding should receive a transvaginal ultrasound to assess for adenomyosis as well as to exclude other structural causes (e.g., polyps, fibroids). Transvaginal ultrasound has a sensitivity of 83.8% and specificity of 63.9% for adenomyosis, and confirmatory testing with magnetic resonance imaging is usually not required. 2\n\nEmpiric therapy may be started before ultrasound results are received. The levonorgestrel intrauterine system is the most-studied treatment, with the largest randomized controlled trial ( n  = 86) showing comparable improvement in hemoglobin and quality of life compared with hysterectomy at 6 months. 5  Other treatments include tranexamic acid, nonsteroidal anti-inflammatory drugs, combined hormonal contraceptives and other progestins (norethindrone acetate, medroxyprogesterone, dienogest). If initial treatment fails after 3–6 months, referral to a gynecologist is suggested, to consider other medical (i.e., gonadotropin-releasing hormone agonists), interventional or surgical options. 1 , 3 , 5\n\nReferral to a fertility specialist is appropriate for patients presenting with subfertility or recurrent miscarriage, especially after the age of 35 years.\nCMAJ  invites submissions to “Five things to know about …” Submit manuscripts online at  http://mc.manuscriptcentral.com/cmaj","source_license":"CC0","license_restricted":false}