GNRH1 and endometriosis: Evidence from a systematic review suggests that administration of a GnRH agonist for 3–6 months before IVF or ICSI in women with endometriosis increases the odds of clinical pregnancy four-fold; this analysis included randomized controlled trials using any GnRH agonist before IVF or ICSI to treat women with any degree of endometriosis diagnosed by laparoscopy or laparotomy (15).