NATF Pride: Presenting Our Latest Action Initiative

This Pride Month, NATF is excited to present an initiative that we’ve been working on for the last year titled Assessing and Addressing the Risk of Venous Thromboembolism (VTE) Across the Spectrum of Gender-Affirming Care.

“The way in which NATF has brought together transgender patients and leading experts to devise recommendations for managing blood clots through a trans-positive lens is a model to keep using for all aspects of trans-inclusive care.”

Troy Keyser, MA (He/Him) 
Patient Advisor

Troy is a transgender man and Vice President of Partnerships at Secure AI Labs, a federated learning and analytics platform for health and life science research.

More than 1 million adults in the U.S. identify as transgender, meaning that they have a gender identity that’s different from their sex assigned at birth. Some transgender individuals pursue medical treatment to align their gender identity with their bodily characteristics; these treatments may include gender-affirming hormone therapy (GAHT) or gender-affirming surgery (GAS). You may also hear the term gender-affirming care, which is an umbrella term that includes GAHT and GAS.

GAHT involves the use of hormones to develop identity-aligning characteristics like facial hair or a change in vocal tone. GAS refers to surgical procedures to also align a person’s internal self and their body; for example, chest or “top” surgery may involve the addition or removal of a person’s chest tissue. 

Robert Goldstein, MD, PhD (He/Him), Project Leader

“Our hope is that we can help clinicians across the country provide better care to folks in the trans community. We’re also hopeful that our work will result in guidance for trans people all across the country to help them understand what their blood clot risk may be and how they might be able to navigate a conversation with their own clinician about gender-affirming care.”

Research shows that gender-affirming care improves mental health and quality of life in transgender people. The inverse is also true: withholding gender-affirming care may cause significantly negative impacts on transgender individuals. But as with all medical therapies and surgeries, gender-affirming care is not without some risk – and the risk for blood clots is important to consider in a patient’s care plan.

Both hormone therapy and surgery are established risk factors for deep vein thrombosis (DVT) and pulmonary embolism (PE). Estrogen is known to raise the risk of blood clots, and several studies have shown an increased risk for blood clots in transgender women using oral estrogen for GAHT. Surgery itself—and the days to weeks following an operation—are considered high-risk periods for the development of blood clots in all patients.

However, most of the evidence we have about blood clot risk is based on studies of cisgender people; that is, people whose gender identity corresponds with their sex assigned at birth. To date, there haven’t been any clinical trials done to explore the risk for DVT or PE in the transgender population.

“All too often the medical treatment of transgender patients, specifically relating to blood clots, is based on limited data. Without a set of best practices to draw from, the transgender community can’t get optimal care,” explains Diva Martinez, a Patient Advisor for the initiative.

“These limited data and lack of consensus on best practices can also lead to clinicians withholding gender-affirming care or requiring transgender patients to stop their hormone therapy for surgeries unnecessarily – a very traumatizing experience for a population already at a higher suicide risk,” says Troy Keyser, another Patient Advisor for the initiative.

Dr. Robbie Goldstein, an expert in LGBTQ health and former Medical Director of the Transgender Health Program at Massachusetts General Hospital, agrees. “When patients come in looking to start GAHT, we have a conversation about the risks and the benefits of hormone therapy. When we talk specifically about estrogen therapy, I mention that there’s a theoretical risk of blood clots. We don’t know the exact risk associated with each type of estrogen that we prescribe to our patients, and we don’t know if there’s a risk for testosterone hormone therapy. That is to say that we don’t have a lot of ‘gold-standard’ evidence to understand exactly what is happening in the trans population as far as blood clot risk – but we do have a tremendous amount of clinical experience.” 

Diva Martinez (She/her), Patient Advisor

Research on blood clot risk must continue to enhance and improve the standards of care used to treat the transgender community. It is only through this vital research and the discoveries made from it that clinicians will be able deliver optimal care to our community.”

Diva is a transgender woman and is currently the Director of Clinical Operations and Development at Alnylam Pharmaceuticals.

Under Dr. Goldstein’s guidance, NATF has brought together clinicians, researchers, and transgender patients from across the country to develop recommendations on managing blood clot risk in transgender individuals. The initiative is currently being peer reviewed.


CisgenderA person whose gender identity aligns with their sex assigned at birth
Gender-affirming hormone therapy (GAHT)Hormonal therapy that aims to align one’s gender identity with their physical characteristics and attributes
Gender-affirming surgery (GAS)Surgical procedures that change sex characteristics to affirm a person’s gender identity
Gender identityA person’s internal sense of their gender
SexSex (male or female) is assigned at birth and typically determined by the appearance of external genitalia
IntersexA term used to refer to situations in which a person is born with reproductive or sexual anatomy that doesn’t align with the typical definitions of female or male sex
Transgender manA man who was assigned female at birth
Transgender womanA woman who was assigned male at birth
Adapted from Swe NC, et al. Metabol Open. 2022 and the It Gets Better Project LGBTQ+ Glossary

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