Most medically assisted procreation (ART) techniques, including oocyte cryopreservation for fertility preservation, involve controlled ovarian stimulation. This procedure uses exogenous hormones, primarily follicle-stimulating hormone (FSH), to promote the development of multiple ovarian follicles in a single menstrual cycle. Once follicles reach a suitable number and size, oocyte retrieval (pick-up) is scheduled after pharmacological ovulation induction.

Human chorionic gonadotropin (hCG) has been routinely used for ovulation induction, but a common complication is ovarian hyperstimulation syndrome (OHSS). Studies have shown that in antagonist protocols, using a gonadotropin-releasing hormone agonist (GnRH-a) instead of hCG reduces OHSS risk. However, GnRH-a triggers luteal phase dysfunction, likely due to depletion of pituitary LH reserves and lack of LH-like activity (present in hCG), resulting in lower clinical pregnancy rates and occasionally very low oocyte yield.

To maximize oocyte retrieval and minimize OHSS risk, a combined "dual trigger" approach using both GnRH-a and hCG has been proposed, leveraging benefits of both agents.

Currently, limited data exist regarding the optimal ovulation induction strategy in oncological patients undergoing fertility preservation via oocyte cryopreservation before gonadotoxic therapy, where maximizing outcomes and minimizing complications is critical.

This study aims to compare the number of oocytes retrieved per cycle in oncological patients undergoing fertility preservation with ovulation induced by either GnRH-a alone or dual trigger (GnRH-a + hCG). It will also assess the oocyte retrieval rate (number of oocytes retrieved/number of follicles aspirated), number of mature oocytes, and incidence of moderate OHSS within 7 days post-retrieval in both groups. Additionally, it will explore correlations between serum estradiol (E2) and luteinizing hormone (LH) levels on the trigger day and oocyte yield.

Approximately 200 patients aged ≥18 years will be consecutively enrolled over 2 years and 2 months. Retrospective period considered: from January 1, 2023, to the study initiation date. Patients will be assigned by clinicians to one of two groups based on clinical characteristics:

Group 1: Ovulation induced with 0.2 mg subcutaneous triptorelin (Decapeptyl®)

Group 2: Ovulation induced with 0.2 mg subcutaneous triptorelin plus 1000-5000 IU urinary hCG (Gonasi®)

Treatment follows standard clinical practice.

Inclusion Criteria:

• Patient with oncological disease eligible for potentially gonadotoxic therapy
• BMI ≥ 17.5 kg/m² and ≤ 32 kg/m²
• Age ≥ 18 years and ≤ 46 years
• AMH > 1.00 ng/mL
• Obtaining written informed consent to participate in the study and for data processing

Exclusion Criteria:

• Hypersensitivity to one or more of the active substances used during the treatment

Patients diagnosed with oncological disease attending the UO Gynecology and Human Reproduction Pathophysiology, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Policlinico di S. Orsola, for fertility preservation through oocyte cryopreservation.