Short-Course Dienogest to Bridge Urgent Fertility Preservation and Surgery in Severe Endometriosis: A Case Report

Background and Clinical Significance: Endometriosis is a chronic, estrogen-dependent inflammatory condition that can cause pain, infertility, and, in its deep infiltrating form, bowel involvement. Dienogest is a progestin that is commonly used for the long-term medical treatment of endometriosis or prior to surgery. Dienogest has been previously used as the progestin in progestin-primed ovarian stimulation (PPOS). However, the use of dienogest as a short-term bridge to maintain disease suppression and prevent ovulation during controlled ovarian stimulation (COS) in patients awaiting surgery has not been well described. This case highlights a novel application of dienogest therapy as a bridging strategy in severe endometriosis, enabling continued disease suppression while facilitating COS and fertility preservation before definitive surgical management; Case Presentation: A 26-year-old nulligravid woman with stage IV endometriosis presented for fertility preservation following hospitalization for small bowel obstruction (SBO) associated with extensive deep infiltrating endometriosis (DIE). Radiologic imaging demonstrated bilateral endometriomas, involvement of the distal ileum, rectosigmoid colon, and adherence of multiple small bowel loops to the right ovary. Following conservative management of the SBO, oral dienogest 2 mg daily was initiated for disease and symptom suppression. Given the extent of the disease, risk of recurrent obstruction and anticipated definitive surgery, oocyte cryopreservation was planned before surgical management. Baseline ovarian reserve testing demonstrated an anti-Müllerian hormone (AMH) of 7.5 pmol/L (1.05 ng/mL) and antral follicular count (AFC) of 3. Approximately one week after dienogest initiation, COS was initiated with recombinant follicle stimulating hormone (rec FSH) 275 IU daily and increased to 300 IU after four days, while dienogest 2 mg daily was continued without additional medications to suppress ovulation. On stimulation day 13, her serum estradiol measured 3280 pmol/L (893.4 pg/mL) and three follicles measured >17 mm. A combined gonadotropin releasing hormone-agonist and human chorionic gonadotropin trigger was administered. Eleven oocytes were retrieved, all of which were mature and cryopreserved. Symptoms did not recur before surgery. Three weeks later, she underwent laparoscopic radical excision of endometriosis, ureterolysis, bilateral ovarian cystectomy, and bowel resection. She was discharged on postoperative day 5 and continued dienogest; Conclusions: In this patient’s case, continuing dienogest during COS provided a dual-purpose bridge, maintaining disease suppression and preventing ovulation during COS, which facilitated fertility preservation with a short interval to planned surgery. Given that this is a single-case study, further research is required to determine safety, efficacy and optimal duration of this approach.