Early Puberty Suppression and Gender-Affirming Hormones do not Alter Final Height in Transgender Adolescents.

Abstract

Early puberty suppression (ePS; Tanner stage 2-3) through Gonadotropin-Releasing Hormone agonists (GnRHa) and gender-affirming hormones (GAH) interferes with growth and may impact final height (FH). To investigate the impact of ePS and GAH on FH in trans boys and trans girls. Retrospective study, including 10 trans boys and 22 trans girls at FH. Bone age (BA) was determined at start of ePS and at start of GAH according to Greulich & Pyle; predicted adult height (PAH) was calculated according to Bayley & Pinneau's tables; target height (TH) was calculated as adjusted mean of maternal and paternal height. TH, PAH and BA were determined according to sex registered at birth (SRAB) and experienced gender (EG). The age at start of PS was 12.37 ± 0.74 years in trans boys and 13.10 ± 1.12 years in trans girls. Total height gain since start of ePS in trans boys was 14.62 ± 4.08 cm, with 70% achieved before start of GAH. In trans girls it was 20.68 ± 7.66 cm, with 61% achieved before GAH. TH for SRAB was the most accurate predictor for FH in both trans boys and girls: the difference with FH was 1.57 cm ± 3.1 (p = 0.168) and -0.98 cm ± 4.17 (p = 0.319) respectively. Also the difference between FH and PAH at the start of PS for SRAB was non-significant in both trans boys and girls (2.62 cm ± 3.79, p = 0.056 and -2.35 cm ± 5.2, p = 0.051, respectively). ePS and GAH do not impact FH, supporting the safety of the treatment; however trans adolescents achieve a FH in line with SRAB, rather than EG.