“Clot rates were twice as high for all transgender women. But in the key subset that had begun estrogen therapy, the odds of developing a potentially-dangerous clot were 5.1 times greater after two years compared with non-transgender males.”
(Gene Emery – Reuters) Hormones given to people to align their sex with their gender pose a significant risk of serious blood clots and stroke among transgender women, one of the largest studies of transgender patients has concluded.
The risk of a dangerous type of blood clot, called a venous thromboembolism, nearly doubles for people transitioning from male to female compared to both non-transgender men and women, researchers reported in Annals of Internal Medicine.
The risk seems to come from hormone therapy. Among transgender women who had started the therapy, the clot risk was five-fold higher after two years of follow-up compared to non-transgender men and three times higher compared to non-transgender women.
And although women have lower rates of heart disease than men, the odds of stroke and heart attack for transgender women remain the same as they would be if they had not transitioned.
For transgender men, the researchers could not confirm any health risks because number of incidents was too small.