Gender-Affirming Hormone Therapy May Not Raise Thrombosis Risk in Transgender Youth

Published April 2021 | Pediatrics

For transgender adults, studies suggest that receiving gender-affirming hormone therapy (GAHT) may be associated with an increased risk of thrombosis, the formation of a blood clot within a blood vessel. However, adolescent and young adult transgender youth do not appear to face a similar increased risk.

In a first-of-its-kind study, senior author Tanya Kowalczyk Mullins, MD, MS, and colleagues examined risk factors and occurrence of thrombosis in a strictly adolescent and young adult transgender population receiving GAHT. Their findings can help patients, families, and clinicians make informed decisions around GAHT for young transgender patients.

Researchers began by conducting a retrospective chart review of 611 patients at a pediatric hospital-associated transgender health clinic. Of these participants, 28.8% were transgender women and 68.1% were transgender men, with a median age of 17 years at GAHT initiation.

Among the cohort, researchers noted multiple thrombotic risk factors, including obesity, tobacco use, and personal and family history of thrombosis. Despite the presence of preexisting risk factors, they found that no youth in their cohort developed thrombosis, suggesting that GAHT in youth does not carry a significant risk of thrombosis in the short-term.

“Our results provide important initial information about the safety of GAHT use in youth that can be incorporated by clinicians into their counseling of these patients and families,” Kowalczyk Mullins says.

Next, researchers will use these results to develop a larger, longer-term study of thrombosis risk associated with GAHT in youth.

Hematologic Evaluation and Incidence of Thrombosis

MTHFR, methylenetetrahydrofolate reductase. —, not applicable. For hematologic testing, results are reported as number of abnormal tests and percentage of patients who had testing performed for which results were abnormal.