GNRH1 and endometriosis: Two nonrandomized trials have shown that prolonging GnRH-a down-regulation before IVF can improve pregnancy and implantation rates in patients with endometriosis undergoing IVF.[9,10] Sallam et al[11] conducted a meta-analysis of 3 prospective randomized trials, including 165 patients with endometriosis treated with GnRH-a for 3 to 6 months prior to IVF cycles.