New treatment strategy for endometriosis using progestin-primed ovarian stimulation with dienogest: A prospective cohort study, comparison of dienogest versus dydrogesterone.

Dienogest (DNG) is an oral progestin effective for the treatment of symptomatic endometriosis, such as reduction of endometrial lesion and control of pain intensity. Progestin-primed ovarian stimulation (PPOS) is a new controlled ovarian hyperstimulation (COH) regimen, and several reports have shown that dydrogesterone (DYG) is an appropriate progestin for PPOS. The purpose of this study was to evaluate the efficacy of DNG in patients undergoing PPOS during COH in comparison with DYG. This was a prospective, cohort, parallel-group, non-inferiority trial of 150 women with endometriosis undergoing assisted reproductive technology between February 2018 and May 2020 at the single fertility center. The assignment to each protocol was based on the optimal treatment for each patient. Patients taking DNG 2 mg continuously were assigned in the DNG group(n = 73). The other patients were allocated in DYG group(n = 77). All viable embryos were cryopreserved for subsequent transfer. The main outcome measures were the mature oocyte and fertilization rates. During this study, no premature LH surge was detected. A smaller number of oocytes were retrieved in the DNG group than in the DYG group (6.18 ± 3.60 vs. 9.85 ± 5.77); however, the rate of mature oocytes was significantly higher in the DNG group than in the DYG group (89.1 % vs. 78.9 %). The fertilization rate was comparable between two groups. Therefore, patients taking DNG for PPOS can continue endometriosis treatment and obtain good-quality embryos during COH. Further prospective randomized-controlled trial should be performed to confirm of this novel strategy of DNG.