Research
Hormonal
Transfeminine hormone therapy is associated with an increased risk of venous thromboembolism (VTE), particularly with oral ethinyl estradiol or conjugated equine estrogen, whereas transdermal estradiol may mitigate this risk.
If you are a transgender woman on hormone therapy, be aware that oral conjugated equine estrogen carries a higher risk of blood clots than oral estradiol or transdermal estrogen. If you have risk factors like smoking, obesity, or a history of blood clots, discuss transdermal estrogen (patch/gel) with your doctor to minimize thrombotic risk.
ModerateQualifiesMEDIUM confidence
In a retrospective review of transgender women in the United Kingdom, transgender women prescribed oral conjugated equine estrogens had increased risk of thromboembolism compared with transgender women taking oral estradiol valerate or ethinyl estradiol. In this cohort, 4.4% of transgender women on oral conjugated equine estrogen experienced a thromboembolic event compared with <1% in transgender women on estradiol or ethinyl estradiol (P = 0.026).
Why this rating
Based on retrospective cohort studies; the paper notes a lack of head-to-head long-term safety studies.
Source
Endocrinology of Transgender Medicine
Guy T’Sjoen et al. · Endocrine Reviews · 2018
DOI 10.1210/er.2018-00011
narrative_reviewCited 313×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
More from this paper
- Gender-affirming hormone therapy significantly reduces mental health morbidity, including depression and anxiety, in transgender individuals.Good
- Transfeminine hormone therapy (estrogen + antiandrogens) induces feminizing physical changes including breast development, fat redistribution, and reduced body/facial hair, but does not significantly alter voice pitch.Good
- Testosterone therapy in transgender men is associated with virilization (deepening voice, increased muscle mass, cessation of menses) and is considered safe regarding cardiovascular and oncological disease in the short- to mid-term.Moderate
Related findings · Hormonal
- Initial treatment for type 2 diabetes should be a combination of metformin and either an SGLT-2 inhibitor or a GLP-1 receptor agonist to achieve cardiorenal protection, rather than monotherapy or older agents like sulfonylureas.Strong
- For patients with specific monogenic obesity syndromes (leptin deficiency, POMC/PCSK1/LEPR mutations), targeted pharmacotherapy (recombinant leptin or setmelanotide) is highly effective and should be prioritized, unlike in polygenic obesity.Strong
- Continued weekly administration of 2.4 mg subcutaneous semaglutide prevents weight regain and promotes further weight loss in adults with overweight or obesity, whereas switching to placebo results in significant weight regain.Strong
This is one finding among thousands. Every one is graded and traced to its source, so you can see what the evidence actually supports. Browse the research →