Transgender Girls Grow Tall: Adult Height Is Unaffected by GnRH Analogue and Estradiol Treatment

Abstract

Context Transgender adolescents can receive GnRH analogues (GnRHa) and gender affirming hormone therapy (GAHT), but little is known about effects on growth and adult height. This is of interest since height differs between sexes and some trans girls wish to limit their growth. Objective Investigate effects of GnRHa and GAHT on growth, and the efficacy of growth-reductive treatment. Design Retrospective cohort study. Setting Specialised tertiary gender clinic. Participants 161 trans girls treated with GnRHa and estradiol at a regular dose (2 mg) or high growth-reductive doses of estradiol (6 mg) or ethinylestradiol (EE, 100-200 µg). Main outcome measures Growth, adult height and difference from predicted adult height (PAH) and target height. Results Growth velocity and bone maturation decreased during GnRHa, but increased during GAHT. Adult height after regular dose treatment was 180.8 ± 5.4 cm which was 2.2 cm below PAH at start GnRHa (95%CI 0.8 to 3.6), and close to target height (-0.2 cm, 95%CI -1.5 to 1.1). Compared to regular dose treatment, high dose estradiol and EE reduced adult height by 1.8 cm (95%CI -0.6 to 4.1) and 4.1 cm (95%CI 0.6 to 7.6), respectively. Conclusion Growth decelerated during GnRHa and accelerated during GAHT. After regular dose treatment, adult height was slightly lower than predicted at start of GnRHa, likely due to systematic overestimation of PAH as described in boys from the general population, but not significantly different from target height. High dose EE resulted in greater reduction of adult height than high dose estradiol, but this needs to be weighed against possible adverse effects.

Interventions to suppress puberty in adolescents experiencing gender dysphoria or incongruence: a systematic review

“…Two studies from the Netherlands found that height growth and bone maturation both decelerated during GnRH-a treatment,80 81 and a third assessing only bone health found the same 83. A Belgian study found stable height growth in birth-registered females but deceleration in birth-registered males 82.…”

“…Of other studies that we are aware have been published since April 2022 until January 2024, very few used a cohort design or an appropriate comparator and were of a similar low quality to moderate quality as the studies summarised in this review. Of those likely to contribute new data for synthesis, five examined physical growth and development,79–83 one cardiometabolic health84 and one psychological health 85. The latter, a study from the US, found that adolescents who received puberty suppression before assessment for masculinising or feminising hormones had fewer symptoms of depression, anxiety, stress and suicidal thoughts compared with those who had not received puberty suppression.…”

Masculinising and feminising hormone interventions for adolescents experiencing gender dysphoria or incongruence: a systematic review

“…Of other studies published since April 2022 until January 2024, very few used a cohort design or an appropriate comparator and were of similar low-quality to moderate-quality. Of those likely to contribute new data to the synthesis, five focused on bone health and growth,83–87 one on cardiometabolic risk88 and two assessed psychological health,89 90 one of which also assessed life satisfaction and congruence with gender identity and appearance,89 and the other additionally assessed body image and sex-typed brain activity 90…”

Dermatological considerations for transgender and gender diverse patients: An Australian perspective

“…6,19 While the development of secondary sexual characteristics is prevented, adolescents continue to undergo linear growth and emotional and cognitive development. 6,20,21 The primary concern with the commencement of GnRH analogues in early adolescence is diminished bone density due to sex steroid deficiency 22 ; however, recent data suggest that this appears to be restored after commencement of GAH. 23 Australian guidelines recommend an initial assessment of bone mineral density and monitoring throughout treatment.…”

“…Puberty suppression is most‐effective when commenced at Tanner stage 2 as it allows individuals to explore their gender nonconformity and development before induction of less reversible GAH treatment (Table 2). 6,19 While the development of secondary sexual characteristics is prevented, adolescents continue to undergo linear growth and emotional and cognitive development 6,20,21 . The primary concern with the commencement of GnRH analogues in early adolescence is diminished bone density due to sex steroid deficiency 22 ; however, recent data suggest that this appears to be restored after commencement of GAH 23 .…”