Menopausal hormone use after hysterectomy in endometriosis: a Finnish register-based study

Objective This study aimed to examine the frequency and type of menopausal hormone therapy (MHT) use after hysterectomy among women with surgically diagnosed endometriosis.Method A retrospective register-based cohort study identified women with a first surgical diagnosis of endometriosis and a reference cohort using Finnish national registries. This study included women aged ≤45 years with hysterectomy and bilateral oophorectomy, and women >45 years with hysterectomy performed between 1996 and 2018. Women with a history of thrombosis, breast cancer or gynecological cancer were excluded. MHT use was identified from national reimbursement registry until the end of 2019.Results Altogether 11,365 women were included: 1748 women aged ≤45 years and 9617 aged >45 years. Among women with endometriosis, 94.3% (aged ≤45 years) and 73.1% (aged >45 years) used MHT postoperatively, compared with 81.8% and 51.5% in the reference cohort (p < 0.001). Estrogen-only therapy was the most commonly used MHT, but the use of combined estrogen–progestin therapy increased significantly (p < 0.001).Conclusion MHT use was very common in women with endometriosis. The shift toward combined therapy reflects evolving international guidance. The high rate of MHT use underscores the need for studies assessing its long-term outcomes in women with endometriosis.