Different progestins in the treatment of endometriosis - are there relevant differences?

Oral progestins without an estrogen component have been described to be effective in the treatment of endometriosis. Several different substances have been tested, which are on the one hand derivatives of the natural progesterone or of the C-17-OH-progesteron, or on the other hand derivatives of C-19-nortestosteron. Their common characteristic is the secretory transformation of estrogen primed uterine endometrium for which different dosages are necessary because of their different biological activities. They are different with regard to their profile and potency of action on hypothalamicpituitary axis, metabolic processes, breast tissue and genital organs. They are effectively similar with regard to endometriosis related complaints if sufficient doses are administered. No effects are noted on reduced fertility in endometriotic patients and the data are inconsistent concerning direct effects on the endometriotic cells.