GNRH1 and polycystic ovary syndrome: In PCOS, treatment with MP can be justified by the multiple potential mechanisms of progesterone implication in the pathogenesis and manifestations of the syndrome (i.e. inadequate production of ovarian progesterone during the luteal phase; decreased hypothalamic sensitivity to progesterone-mediated negative feedback due to hyperandrogenemia-induced impairment of progesterone regulation of GnRH pulsatility) [101–102].