Health considerations for transgender women and remaining unknowns: a narrative review

Transgender (trans) women (TW) were assigned male at birth but have a female gender identity or gender expression. The literature on management and health outcomes of TW has grown recently with more publication of research. This has coincided with increasing awareness of gender diversity as communities around the world identify and address health disparities among trans people. In this narrative review, we aim to comprehensively summarize health considerations for TW and identify TW-related research areas that will provide answers to remaining unknowns surrounding TW's health. We cover up-to-date information on: (1) feminizing gender-affirming hormone therapy (GAHT); (2) benefits associated with GAHT, particularly quality of life, mental health, breast development and bone health; (3) potential risks associated with GAHT, including cardiovascular disease and infertility; and (4) other health considerations like HIV/AIDS, breast cancer, other tumours, voice therapy, dermatology, the brain and cognition, and aging. Although equally deserving of mention, feminizing gender-affirming surgery, paediatric and adolescent populations, and gender nonbinary individuals are beyond the scope of this review. While much of the data we discuss come from Europe, the creation of a United States transgender cohort has already contributed important retrospective data that are also summarized here. Much remains to be determined regarding health considerations for TW. Patients and providers will benefit from larger and longer prospective studies involving TW, particularly regarding the effects of aging, race and ethnicity, type of hormonal treatment (e.g. different oestrogens, anti-androgens) and routes of administration (e.g. oral, parenteral, transdermal) on all the topics we address.