Growth after pubertal block in trans adolescents

Transgender people show incongruence between the sex assigned at birth and the gender they identify with. Puberty generates hormonal changes that induce physical changes, with the development of secondary sexual character, which cause great discomfort in the transgender individual. It is also a vital time when there is an increase in the rate of growth. The drug GnRHa stops puberty, slowing down the changes in the body and allowing the adolescent time to consider their gender identity. However, an expected side effect of these drugs is that growth velocity is affected.

To determine the growth velocity of adolescents and transgender children undergoing pubertal blocking therapies.

We conducted a longitudinal study using anthropometric and laboratory measurements every 6months, collected 1year before and 2years after blockade, to assess whether growth velocity and height are affected by pubertal blockade. The comparison was made using the standard deviations of the variables according to age, using the Wilcoxon signed-rank test in paired groups and the U-Mann Whitney test in independent groups. To obtain the data, we reviewed the medical records of the participants in our study.

Fifty-five transgender adolescents initiating pubertal blocking with a median age of 11.8years are studied. It is observed that height measured in standard deviations (SD) and growth velocity, measured in centimetres and SD, decrease in accordance with increasing time in pubertal block. When comparing transgender boys and girls, transgender girls show a greater decrease in height SD. These differences are statistically significant for pre-blocking, 6 and 12months of BP therapy (P=.036, P=.005 and P=.042 respectively). In addition, it was also observed that growth velocity was more affected in trans girls than in boys, although these differences were not statistically significant.

Height and growth velocity are decreased when puberty is blocked. This decrease is more striking in transgender girls than in transgender boys.