Pretreatment with dienogest in women with endometriosis undergoing IVF after a previous failed cycle

Research question: The major causes of IVF failure in women with endometriosis have been attributed to decreased ovarian reserve, low embryo quality and impaired receptivity of the endometrium. Dienogest (DNG) has anti-inflammatory and anti-angiogenic activity and so may theoretically improve IVF outcomes in women with endometriosis. This study aimed to evaluate the administration of DNG before IVF in women with endometriosis who had previously failed one IVF cycle. Methods: This study was based on the retrospective analysis of a prospectively collected database, including 151 women who had failed a previous IVF cycle and all subsequent embryo transfers and had an imaging diagnosis of endometriosis. Patients either directly underwent IVF without receiving hormonal treatment or received 3 months of treatment with DNG (2 mg/daily) before IVF. Results: Eighty-eight (58.3%) patients underwent IVF without previous hormonal treatment, and 63 (41.7%) received pretreatment with DNG. The cumulative implantation, clinical pregnancy and live birth rates were significantly higher in the DNG-treated group (39.7%, 33.3% and 28.6%) than in the non-treated group (23.9%, 18.2% and 14.8%; P = 0.049, 0.037 and 0.043, respectively). The largest diameter of endometriomas significantly decreased after DNG pretreatment (P < 0.001). The use of DNG increased significantly the number of oocytes retrieved (P = 0.031), two-pronuclear embryos (P = 0.039) and blastocysts (P = 0.005) in women with endometriomas of diameter ≥4 cm. Conclusions: This study suggest that in patients with endometriosis, IVF outcomes can be improved by pretreatment with DNG. In particular, the use of DNG allows for better oocyte retrieval and blastocysts in patients with large endometriomas.