ESPE Yearbook of Paediatric Endocrinology

Pediatrics. 2021 Mar 22:e2020023549. doi: 10.1542/peds.2020-023549. PMID: 33753543.

This retrospective, single center chart review study assessed the incidence of arterial or venous thrombosis during gender affirming hormone therapy (GAHT) in 611 transgender adolescents. The prevalence of thrombosis risk factors was also investigated. No increased risk of thrombosis was found over a short time period in trans-females and trans-males, even when thrombosis risk factors were identified in some individuals.

In recent years, the numbers of youth identifying as transgender increased enormously and the requests for hormonal treatments shifted to ever younger ages. Effects and adverse effects of drugs may not be the same in youth as in mature adults. As is well-known for birth control pills, some hormonal treatments significantly increase thrombosis risk. In contrast to the reassuring findings reported here by Mullins et al., data in adults on GAHT suggested significantly increased thrombosis risk for trans-females but not trans-males (1). Duration of hormonal treatment, route of administration and age may have variable influence. Many studies of adverse hormonal treatment effects suffer from limitations such as: small numbers, retrospective design, single centre focus, non-uniform study protocols, or short observation period. Many unsolved questions in transgender medicine, especially with a perspective on long-term health consequences, will only be solved by joining forces and creating an international registry to collect sufficiently large datasets in a standardised manner.

Reference: 1. Luuk J J Scheres, Nienke L D Selier, Nienke M Nota, Jeske J K van Diemen, Suzanne C Cannegieter, Martin den Heijer. Effect of gender-affirming hormone use on coagulation profiles in transmen and transwomen. J Thromb Haemost. 2021 Apr;19(4):1029–1037. doi: 10.1111/jth.15256.