Progestagens and anti-progestagens for pain associated with endometriosis.

Endometriosis is a chronic inflammatory condition defined by the presence of glands and stroma outside the uterine cavity. It occurs in 7% to 10% of all women of reproductive age and may present as pain or infertility. The pelvic pain may be in the form of dysmenorrhoea, dyspareunia or pelvic pain. Initially a combination of estrogens and progestagens was used to create a pseudopregnancy and alleviate the symptoms associated with endometriosis. Progestagens alone or anti-progestagens have been considered as alternatives because they are inexpensive and may have a better side effect profile than other choices.