P-603 Combined oral contraceptive pill (COCP) before controlled ovarian hyperstimulation (COH) in donors could negatively affect egg donation outcomes in recipients: a multicentre retrospective study

Abstract

Abstract Study question Could COCP use before COH with a progestin primed ovarian stimulation protocol (PPOS) in donors also negatively influence the egg donation outcomes in recipients? Summary answer Synchronization with a combined oral contraceptive pill (COCP) before controlled ovarian hyperstimulation (COH) involving progestin for pituitary suppression shows worst outcomes in egg donation treatments. What is known already It is well known that COCP leads to a long-lasting pituitary suppression, a reversible reduction in AMH and antral follicle count with higher risk of inappropriate response to COH and GnRH-agonist trigger, potentially reducing number and quality of retrieved oocytes. This is supported by the latest international guidelines on COH that strongly discourage COCP use before GnRH antagonist protocols because of a reduced efficacy of such cycles, also, in terms of ongoing pregnancy rate (OPR). They also underlie that interactions between COCP pretreatment and PPOS protocols remain inadequately explored and more research are needed to clarify discrepancies persisting in literature. Study design, size, duration Multicentre retrospective cohort study evaluating egg donation outcomes, depending on the use or not of COCP pre-treatment in donors, in terms of OPR, Live Birth Rate (LBR), and secondly of fertilization rate (FR), blastulation rate (BR), implantation rate (IR) and miscarriage rate (MR). The treatments were realized in a Private Fertility Clinic (where donors also underwent COH with PPOS protocol) and a public hospital (transnational egg donation program) between January 2022 and September 2023. Participants/materials, setting, methods 216 egg donation cycles were studied. Excluding cases of fertilization and/or embryo development failure and cases for which embryo transfer outcomes were not available at the time of data collection, the study analysed the outcomes of 90 embryo transfers (ETs). After the first analysis on total cycles, a stratification was made to evaluate whether COCP could have a different influence depending on the oocytes type used: fresh or vitrified. Main results and the role of chance COCP-No and COCP-Yes groups show similar FR and BR, after donation of same oocytes number (6,4 ± 1,1 vs 6,5± 1). Interestingly, vitrified oocytes from COCP-Yes donors produced a statistically lower yield of viable blastocysts (22,2% versus 37,9%; p = 0,007). IR was higher in the COCP-No group, (46,4% vs. 28,6%), data confirmed also in the two subgroups (fresh: 42,9% vs. 14,3%; vitrified: 48,8% vs. 35,7%). Higher MR was observed in the COCP-Yes group, achieving statistical significance both for total oocytes (66,7% vs. 9,4%; p = 0,006) and vitrified ones (60% vs. 5%; p = 0,016). Pregnancy rate was higher in the COCP-No group (46,4% vs. 28,6%), the same trend was found regardless of the type of oocytes used (fresh: 42,9% vs. 14,3%; vitrified: 48,8% vs. 35,7%). The greatest discrepancies were observed in OPR and LBR subcategories. In fact, a statistically higher OPR was obtained in the COCP-No group (42% vs. 9,5%, p = 0,008), which leads to a statistically higher LBR (30,4% vs. 0%; p = 0,004). Notably, the LBR after using both fresh and vitrified oocytes was markedly higher in the COCP-No group (fresh: 28,6% vs. 0%, p = 0,385; vitrified: 31,7% vs. 0%, p = 0,041), presenting a significant difference when vitrified oocytes were used with potential clinical relevance. Limitations, reasons for caution The main limitation lies in the retrospective nature of the study and the small sample size, but the multicentre design gives greater reliability. Further research is needed to confirm these findings and better understand the specific circumstances in which COCP may or may not be beneficial. Wider implications of the findings COCP pretreatment in egg donors undergoing PPOS protocol may negatively impact embryo development and pregnancy outcomes in recipients, with increased MR, and reduced OPR, and LBR. Particularly, the worst outcomes involve vitrified oocytes, providing valuable insights to reconsider COCP use in transnational egg donation programs, but also fertility preservation ones. Trial registration number Not Applicable