Embryos Derive from Delayed Mature Oocyte should be Cryopreserved and Favorable to Transfer in a following Endometrium Synchronize Frozen-thawed Cycle

Hila Gitman 1 Meirav Noach-Hirsh 1 Olga Dratviman-Storobinsky 1 Keren Slabodnik kaner 1 Ravit Nahum 1,2 Jigal Haas 1,2 Raoul Orvieto 1,2,3 Adva Aizer 1,2
1Department of Obstetrics and Gynecology, Chaim Sheba Medical Center, Israel
2Sackler Faculty of Medicine, Tel Aviv University, Israel
33. The Tarnesby-Tarnowski Chair for Family Planning and Fertility Regulation, at the Sackler Faculty of Medicine, Tel-Aviv University, Israel

Oocyte eligible for Intracytoplasmic Sperm Injection (ICSI) are those that progressed through meiosis to MII. The remaining delayed mature oocytes can be injected, aiming to achieve more embryos and better chance to conceive. We aimed to assess the outcome of delayed matured oocytes, derive from either GV or MI, that reached maturity (MII) 24 hours following retrieval. The study population consisted of 362 women who underwent 476 IVF cycles. While fertilization rates were comparable between the sibling delayed mature oocyte group compared to injection on day 0 group (58.4% vs 62%, respectively, p=0.07), the top quality embryo rate per injected MII day 0 oocyte was significantly higher as compared to day 1 injected oocyte (57.5% vs 43.9% respectively, p