Oocyte Maturation

The goal of this clinical trial is to learn whether the sudden administration of vaginal micronized progesterone during the late follicular phase can trigger an LH surge and reactivation of oocyte meiosis in healthy oocyte donors aged 18 to 33 undergoing a mild ovarian stimulation cycle. The main question it aims to answer is: * Does progesterone administered in the late follicular phase induce an LH surge and subsequent oocyte meiosis reactivation? Participants will: * Undergo a mild ovarian stimulation with 75 IU of follitropn alfa * Start vaginal micronized progesterone (400 mg every 12 hours) once at least one follicle reaches 15 mm * Have blood samples collected to measure hormone levels before and after progesterone administration * Undergo oocyte retrieval 35-36 hours after the progesterone trigger This is a low-intervention, single-center pilot study including approximately 10 oocyte donors.

This single-center randomized sibling-oocyte controlled trial evaluates whether co-culture with induced pluripotent stem cell (iPSC)-derived ovarian support cells (OSCs) improves rescue in vitro maturation (r-IVM) outcomes of surplus germinal vesicle (GV) oocytes collected during routine IVF treatment. Eligible GV oocytes from each enrolled participant are allocated within participant in a 1:1 ratio to either conventional r-IVM or r-IVM with OSC co-culture. The primary outcome is the metaphase II (MII) maturation rate after 24 hours of culture. Secondary outcomes include fertilization rate, day 3 embryo formation, good-quality day 3 embryo rate, blastocyst formation, and good-quality blastocyst rate. All embryos generated in the study are for research purposes only and will not be used for clinical embryo transfer.

Folliculogenesis involves the recruitment of primordial follicles into a group of growing follicles in which eventually one follicle is selected, matured and ovulated. Complex endocrine and intra-ovarian paracrine interactions occur to create a changing intra-follicular hormonal milieu suitable for oocyte development. However, this oocyte developmental competence and to undergo fertilization and embryogenesis is impaired in aged women. Diminished ovarian function is generally attributed to decreased quantity and quality of oocytes and their surrounding granulosa cells during ovarian aging, although the underlying mechanisms remain unclear. The aim of the study is to investigate the miRNA in (follicular fluid) FF exosome in young and aged women and their relationship to egg maturation.