The adolescents cared for by the Dutch clinicians are mainly first seen before, or at an early stage of, puberty. For those confirmed as experiencing profound gender dysphoria that is highly likely to persist, hormone blocking medication is offered at a testicular volume of 6-8 ml to suspend puberty, thereby relieving immediate stress and providing more time for diagnosis. However, some adolescents are first seen at later stages of puberty or even after pubertal development is complete. These cases too are carefully screened and medication is administered to block endogenous sex hormones before feminising hormones are offered.
The opinion of the Dutch clinicians is that, for adolescents born with male phenotype who have already reached a late stage of pubertal development, 5 mcg ethinylestradiol is very low. For such adolescents, in contrast to the British approach, they do not undertake a slow initiation of puberty, but increase the dose of medication in relation to breast development. They do not use ethinylestradiol but 17 beta estradiol, the natural estrogen. For 17 beta estradiol they progressively increase the dose to 2mg per day which they say is an adult dose and comparable with 30-50 mcg ethinylestradiol. This is higher than the 20-30 mcg offered by the British clinicians.
Monitoring breast development as a guide to dosage, rather than increasing it in pre-determined steps, accords with clinical experience of other conditions. In taking young girls through puberty, if you increase estrogens abruptly, they sometimes get uncomfortable breast development with an abnormal breast profile – characterised by increase in the areola, which gives a curious double hump. Whether the same would happen in an older breast is unclear. Although it is doubtful that quite the same caution would be warranted, careful monitoring seems appropriate.
The Dutch use of 17-beta estradiol seems warranted. The dose of ethinyl estradiol necessary to feminise a transsexual adolescent, who has already completed full male puberty, may even be as high as 100 mcg daily. At such dosage levels there is reported to be a substantially greater thrombotic risk than in using 17-beta estradiol (reference below).
A. W. F. T. Toorians, M. C. L. G. D. Thomassen, S. Zweegman, E. J. P. Magdeleyns, G. Tans, L. J. G. Gooren and J. Rosing; Venous Thrombosis and Changes of Hemostatic Variables during Cross-Sex Hormone Treatment in Transsexual People The Journal of Clinical Endocrinology & Metabolism 2003; Vol. 88, No. 12 5723–5729