A selective progesterone receptor modulator (SPRM) is an agent that acts on the progesterone receptor. A characteristic that distinguishes such substances from receptor full agonists and full antagonists is that their action differs in different tissues (agonist in some while antagonist in others). This mixed agonist/agonist profile of action leads to selective stimulation or inhibition progesterone-like action in different tissues and furthermore raises the possibility of dissociation of desirable therapeutic effects from undesirable side effects in synthetic progesterone receptor drug candidates.