XVII Harry Benjamin International Gender Dysphoria Association Symposium
31 October - 4 November 2001, Galveston, Texas, U.S.A.

Venous Thrombo-Embolism and (Oral) Estrogen Use

TOORIANS, A.W.F.T. The Netherlands
Co-authors: L.J.G. Gooren & H. Asscheman (The Netherlands)

(Oral) estrogen therapy is sometimes associated with venous thrombo-embolism. In our clinic the normal treatment regimen is 100-microgram ethinyl-estradiol and 100 mg cyproterone acetate. On the basis of an earlier analysis that venous thrombo-embolism occurs mainly in subjects over 40 years of age, we recommend transdermal estradiol for this group. The third generation contraceptives are associated with a higher degree of thrombo-embolism than the second generation, probably due to the new progestin component. We have no indication that cyproterone acetate (which has progestational properties) has contributed to thrombo-embolism in our subjects. From 1976 on 1364 male-to-female transsexual have been treated with the above regimen and we have observed a total of 40 vascular complications. Thirty-four subjects had venous thrombo-embolism of whom seven had pulmonary embolism, a potentially life-threatening condition. Five persons had thrombophlebitis and one arterial embolism. Risk factors for thrombo-embolism in general are a high body mass index, smoking and the dose of estrogens used. Disorders in clotting proteins such as protein C and S and factor V Leiden, may predispose to the development of venous thrombo-embolism. Their presence can be suspected from a family history of venous thrombo-embolism. In the future it may be desirable to screen candidates for estrogens for pathology of the above clotting factors. Upon review of our patient records we feel that the family history has not always been sufficiently explored. Further, a number of subjects had overdosed themselves, sometime up to five times the prescribed dose of ethinyl-estradiol. Two-thirds of our male-to-female transsexuals smoke, which is another risk factor for the development of venous thrombo-embolism. The conclusion must be that elaborate counseling for subjects receiving estrogen be necessary.