GNRH1 and endometriosis: Hormonal therapies, such as GnRH agonists [21,22] and the progestin dienogest (DNG) [23] administered prior to ART have also been reported to enhance clinical pregnancy rates, but recent systematic reviews have debunked the effects of GnRH agonists [24] and DNG [25], suggesting that it is difficult to expect that drugs alone can improve ART outcomes in endometriosis patients.