While inducing similar progesterone levels, the ratio of 5 alpha- and
5 beta-pregnanolone/progesterone plasma concentrations has been dramat
ically increased after oral as opposed to vaginal administration, in a
cross-over study. The known psychotropic effects of 5 alpha- and 5 be
ta-pregnanolone lead to different indications and precautions for oral
and vaginal administration of progesterone.