Low estrogen doses are effective to keep estradiol and testosterone serum levels at normal premenopausal women in male-to-female transsexuals

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: MON 586-595-Reproductive Axis Determination, Development & Transgender Medicine
Basic/Clinical
Monday, June 17, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board MON-595
Flávia Siqueira Cunha*1, Sorahia Domenice1, Maria Helena Palma Sircili2, Elaine Maria Frade Costa1 and Berenice Bilharinho Mendonca1
1Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil, 2Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
INTRODUCTION: The recommended estrogenic dosage for feminization of male-to-female transsexual (MtFT) people is usually two to three times higher than that for hormone replacement therapy in postmenopausal women. The purpose of hormone therapy in MtFT people is to maintain estradiol (E2) and testosterone (T) levels at their normal range for premenopausal women at follicular phase.The use of higher doses of estrogens is associated with an increased risk of venous tromboembolic disease, pulmonary embolism, myocardial infarction, stroke, and adverse liver effects. These collateral effects of high-dose estrogens therapy have been described in MtFT people, as well as an increase in prolactin (PRL) levels and even prolactinoma. OBJECTIVE: To evaluate LH, FSH, T, E2 and PRL levels after low-dose estrogens therapy associated or not to cyproterone acetate (CA) in MtFT subjects. PATIENTS AND METHODS: 57 MtFT (46,XY karyotype) were evaluated before gonadectomy. They had a mean age of 38.5 ± 7.7 yrs (23 to 58 yrs) and the referred age at the start of hormone therapy (supervised or not) was 22.3 ± 6.7 yrs. Hormone therapy consisted of estrogen alone and estrogen combined with cyproterone acetate (CA) in 10 and 47 patients, respectively. The daily doses of estrogens were: conjugated equine estrogen (CEE) 0.625 mg (41 subjects) or 1.25 mg (10 subjects); ethinyl estradiol (EE) 0.03 mg (4 subjects) or 0.06 mg (1 subject); or estradiol valerate 2 mg (1 subject). The daily doses of CA were 50 mg (46 subjects) and 100 mg (1 subject). RESULTS: Estrogen therapy (estrogen alone and estrogen plus CA) reduced T levels from 764 ± 279 ng/dl to 27 ± 19 ng/dl, as well as LH and FSH levels (8.4 to 1.0 U/L and 13 to 1.8 U/L, respectively). Serum levels of T, E2, FSH and PRL of the patients treated with estrogen alone or estrogen plus CA were not statistically different (p=0.16, p=0.50, p=0.58 e p=0.15, respectively), whereas LH levels were significantly higher in ‘estrogen alone’ group (p=0.008). CONCLUSION: We concluded that in MtFT subjects, lower estrogen doses than the ones recommended in the guidelines are effective to keep E2 and T levels at normal premenopausal women range, avoiding the use of higher estrogen doses potentially associated with several side effects.

(1) Hembree WC et al. Endocrine treatment of transsexual persons: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab 2009; 94:3132-54.

Nothing to Disclose: FSC, SD, MHPS, EMFC, BBM

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

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