ultimately lead to an acceleration of cardiovascular disease, osteoporosis and cognitive decline. Hormone therapy (HT) is an effective treatment for many women. Nevertheless, in women with significant endometriosis, estrogen may cause an exacerbation of pain associated with endometriosis. In a study of patients with endometriosis, women who underwent hysterectomy with ovarian conservation had a 6-fold greater risk of developing recurrent pain and an 8-fold greater risk of reoperation (3). It has been suggested that HT may reactivate residual endometriosis or even produce new implants in climacteric women with a history of endometriosis (4). At the same time, there is evidence that endometriosis may also occur in postmenopausal women who do not receive HT. In some women there is also the potential risk of malignant transformation of endometriosis lesions after menopause, occurring either spontaneously or in association with HT (5). Accordingly, we wished to determine what the true risks are of prescribing HT to women after menopause with a history of endometriosis, and to seek data on types of HT in this setting. Methods We used Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for this systemic review (Fig. 1).