ESPE Abstracts

Background: Progestins such as lynestrenol (L) can be used in female to male (FtM) adolescents with gender dysphoria (GD) who have advanced pubertal development to reduce the psychological burden of menstruation. L can later be combined with cross-sex hormones (testosterone esters) (L+T). L is much cheaper and easier to administer than GnRHa. To date, few data exist on the (side) effects of progestins for this indication.

Objective and hypotheses: To report the effects of consecutive L (5 mg) and L+T in FtM adolescents with GD on antropometrics, biochemical, hormonal parameters and side effects.

Method: Retrospective analysis of clinical and biochemical data in 45 FtM adolescents treated with L monotherapy for 12.6 months and L+T for 11.4 months. Statistical analysis: McNemar’s, paired Student-t or Wilcoxon signed-ranks test (as appropriate). All participants were advised to take vitamin D supplements (25,000 U/ml) and a calcium-enriched diet.

Results: Metrorrhagia of variable intensity and acne were most pronounced during the first months of monotherapy and combination therapy respectively and decreased thereafter. Headaches, hot flushes and fatigue were the most reported side effects. During treatment, a gradual increase in musculature, hemoglobin, hematocrit, creatinine and liver enzymes was seen, progressively sliding into male references. Lipids shifted to a more unfavourable HDL/LDL ratio; glucose metabolism was not affected. SHBG, total testosterone and estradiol levels decreased and free testosterone slightly increased during monotherapy. Total and free testosterone increased significantly during combination therapy. Gonadotropins were only fully suppressed during combination therapy. AMH remained stable. Most changes occurred in the first six months of the respective treatment phases and remained stable thereafter.

Conclusion: Treatment with L is effective, safe and inexpensive. However, suppression of gonadotropins is incomplete. Higher doses may be needed to obtain immediate and full suppression of menstruation.