Endocrine Abstracts

Introduction: Adolescents with persistent gender dysphoria (GD) receive GnRH analogues to achieve pubertal arrest. It is unclear whether this is adequate to achieve biochemical suppression of gonadotrophin (LH, FSH) and sex hormone production.

Methods: Gonadotrophins, testosterone and oestradiol were measured in GD patients (15–18 years) before and after monthly Gonapeptyl treatment (3.75 mg i.m.). Patients administered other analogues and/or cross-sex hormones were excluded. For data analysis, undetectable measurements were substituted for the assay’s quantitation limit. Biochemical suppression was defined as undetectable gonadotrophins and oestradiol (natal females) or testosterone (males).

Results: Seventy four patients (25 males, 49 females) were treated with Gonapeptyl for a median of 7 months (IQR 6–8). Gonadotrophins were lower following treatment. However, most patients did not achieve complete biochemical suppression. In females, only 14 and 64% achieved complete LH and oestradiol suppression respectively. No males completely suppressed LH and only 20% had undetectable testosterone. FSH was not adequately suppressed in any patients. There was no correlation between age, treatment duration, or body size with responses to Gonapeptyl.

Discussion/conclusion: The majority of patients did not achieve complete biochemical suppression of gonadotrophin or sex hormone production on Gonapeptyl treatment. The suppression was more marked in females than males. No effect was seen when adjusting for body size. The optimal treatment to arrest puberty in GD patients needs a consensus view. Pragmatically, a significant fall in testosterone or oestradiol accompanied by LH suppression and clinical pubertal arrest could be considered adequate.