Background: The role of micronised progesterone in hormone regimens for transgender (trans) individuals undergoing feminising hormone therapy remains uncertain, though there are anecdotal reports of improved mood and enhanced breast development. We hypothesised that micronised progesterone would improve sleep quality, psychological stress and breast development in trans individuals on established feminising hormone therapy.
Methods: We conducted a three-month prospective, observational case-control study of 23 trans individuals newly commencing 100mg micronised progesterone and 19 controls continuing standard care therapy. Outcome measures included (i) Pittsburgh Sleep Quality Index (PQSI); (ii) Kessler psychological distress (K10) scale; and (iii) Tanner stage. A linear mixed model was used to compare mean differences between groups.
Results: Compared to controls over 3 months, there was no difference in PSQI [mean difference 0.163 95% CI (-1.86, 2.19) P=0.87), K10 [1.129 95% CI (-1.68, 3.94) P=0.43] or Tanner stage [0.126 95% CI (-0.22, 0.47) P=0.46]. There was no statistically significant difference in the proportion of individuals with clinically significant improvements in PSQI (25% vs. 17%, P=0.70) or K10 (20% vs. 11%, P=0.66). One individual had a significant deterioration in psychological distress that improved following cessation of micronised progesterone.
Conclusions: Micronised progesterone was not associated with changes in sleep quality, psychological distress or breast development over three months follow-up, though there was significant inter-individual variability. Larger, placebo-controlled trials are required to further evaluate different doses of micronised progesterone in feminising hormone therapy regimens.