Could a simple hormone pill replace the ovulation shot?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Informed Consent Form dated and signed correctly prior to the performance of any study procedure. * Oocyte donors aged \>17 and \<34 years old in the moment of the recruitment. * Patients with regular menstrual cycles (between 25 to 35 days long). * Generally healthy women with no history of endocrine disorders (e.g., polycystic ovary syndrome (PCOS) or significant systemic disease). * Body Mass Index (BMI) between 18.5 and 28. Exclusion Criteria: * Presence of ovarian cyst(s) detected on the baseline (initial) ultrasound examination. * Untreated endocrine conditions (polycystic ovary syndrome (PCOS), uncontrolled thyroid dysfunction and hyperprolactinemia). * Hypogonadotropic or hypergonadotropic hypogonadism. * Known hypersensitivity or clinical contraindication to the administration of vaginal progesterone or its excipients. This includes, but is not limited to: active deep vein thrombosis or thromboembolic disorders, known or suspected estrogen- or progesterone-dependent neoplasia, undiagnosed abnormal genital bleeding, porphyria, or severe hepatic dysfunction. Additionally, patients with anatomical abnormalities of the vagina that preclude the proper insertion or absorption of the vaginal insert are excluded. * Any condition contraindicating vaginal ultrasound and/or vaginal oocyte retrieval.These include: active pelvic inflammatory disease (PID), acute vaginal or cervical infection, or presence of pelvic malignancies. Patients with significant anatomical distortions or vascular anomalies in the pelvic region that, in the investigator's opinion, would make oocyte retrieval technically unfeasible or pose an unacceptable risk of hemorrhage or injury to adjacent organs, are also excluded. * Use of hormonal contraceptives (oral, patch, or ring) or GnRH analogues within the month preceding the study. Note: Participants who have discontinued these or other prohibited medications for a period of at least 30 days are eligible for rescreening starting at Visit 1. * Participation in any other ongoing clinical trial or use of investigational drugs within the last 30 days.