Replacement of missing oestrogen and progesterone.
In younger women with KS / CHH oestrogen only is used at first in order to maximise secondary sexual characteristics before the use of progesterone.
The oral contraceptive pill is sometimes used to deliver both oestrogen and progesterone, especially the 3 monthly version which produces a "bleed" every three months rather than monthly.
Both oestrogen and progesterone are essential to maintain bone density and healthy uterine lining.