Luteal Phase Ovarian Stimulation With Follitropin Delta and Dydrogesterone

The last decade has shown a progressive scientific interest for new strategies to improve the outcomes of controlled ovarian stimulation (COS). Given the fact that interovulatory period has been described to have multiple waves of follicular recruitment, luteal phase ovarian stimulation (LPOS) has been proposed as new protocol for COS, with satisfactory ovarian response and pregnancy outcomes. On the other hand progestin-primed ovarian stimulation (PPOS) is today considered an innovative protocol aiming to achieve multi-follicle recruitment and block the luteinizing hormone (LH) surge through progesterone administration in place of the traditional down regulating or gonadotropin-releasing hormone (GnRH) antagonist. This protocol has been shown to be equally effective as LH suppression with GnRH antagonist reporting equivalent oocyte retrieval rates, endocrine profiles, viable embryo numbers, and pregnancy outcomes. Due to the feasibility and patients-friendly characteristics of PPOS in oocytes donors, the current study aims to investigate the impact on the number of cumulus-oocyte complexes (COCs) when a PPOS protocol is associated to both conventional follicular phase stimulation and LPOS for vitrification of oocytes in oocyte donors. Moreover, it aims to determine whether LPOS using PPOS protocol has comparable outcomes to conventional follicular phase stimulation with PPOS protocol, in oocyte donor patients.