P-165 Artificial removal of the zona pellucida at the pronuclear stage in patients with poor quality embryos with severe fragmentation

Abstract Study question Is artificial removal of the zona pellucida (ZP) at pronuclear stage effective in patients with poor quality embryos severe fragmentation? Summary answer Artificial ZP significantly improved culture results fragmentation. What is known already In 2020, Yumoto et al. first reported that (ZP-free) decreased rate fragmentation and outcomes 3 pronuclei (3PN) reaching to good blastocysts. Therefore, may not always be necessary for normal embryonic development after stage. The same group presented 37th ESHRE meeting 2021, blastocyst transfer ZP-free embryo 2 (2PN) resulted pregnancy two poor-quality resulting live births. design, size, duration This study included 211 2PN from 46 cycles 30 couples obtained between July 2021 December 2022, whose previous oocyte retrieval cycle showed massive cytoplasmic cleavage confirmed by a time-laps incubator (TLI). Average age women was 38.8years. were cultured TLI up 7 days. All blastocysts cryopreserved future cycles. Participants/materials, setting, methods participants provided written informed consent, Institutional Review Board approval obtained. performed following procedure. 1) Embryos placed 0.125M sucrose-containing HEPES cytoplasm shrinking. 2) without adhesion removed laser system. 3) Ooplasms completely separated blowing medium point like jet car wash. 4) Main role chance Day divided into groups using Veeck’s classification: 8 cell grade or higher defined as good, 4 5 regardless number cells poor, others fair. We compared (ZP-intact). For day embryos, fair 19.4% (41/211), 62.6% (132/211) 18.0% (38/211) 2.9% (15/561), 37.4% (210/561), 59.9% (336/561) past, respectively (p < 0.001). Good-quality 3BB more on Gardner’s classification. As blastocysts, good-quality rates 45.0% (95/211) 27.0% (57/211) 23.0% (112/488) 6.8% (33/488) Of these, transfers 11 clinical pregnancies. had births any congenital anomalies one miscarriage. One delivered 33 weeks gestation caesarian section, mother gestational diabetes. Limitations, reasons caution retrospective control conducted only single fertility center. It conduct sibling oocytes demonstrate effectiveness culture, create criteria who are benefit culture. Moreover, safety should evaluated. Wider implications findings reduced fragments might bring light have difficulty obtaining Trial registration Not Applicable