Progesterone in gender-affirming therapy of trans women

Table 1 Known physiological actions of progesterone

Uterine endometrium	Inhibition of proliferation and differentiation of the endometrium into a secretory organ for the potential implantation of a fertilised ovum
Uterine cervix	Inhibition of cervical mucus secretion
Breast tissue	Ductal side branching and lobulo-alveolar development; increase of the areolar size
Skeleton	Bone formation (in conjunction with oestradiol)
Arterial endothelium	Amplification of the actions of endogenous nitric oxide
Brain	Mitigation of central stress hormone responses; induction of deep sleep