P-255 Increased time in thawing solution improves human oocyte warming outcomes

Abstract Study question Can increased time in thaw solution improve oocyte survival and outcomes following vitrification/warming? Summary answer Exposing vitrified oocytes to the first step thawing for 90 seconds improved compared 60 second exposure. What is known already Oocytes are a sensitive cell type careful handling of cells required obtain high vitrification warming. Carefully timed exposure various solutions avoid toxicity ensure proper vitification. Similarly, carefully warming damage upon Recent reports suggest modified rapid protocol may be beneficial blastocysts. However, unique require considerations optimize design, size, duration Retrospective analysis donor outcome data within single IVF lab over 12 month period comparing during (control n = 637 oocytes) versus very consistent (n 672 solution. Participants/materials, setting, methods Human were using standard Kitazato with ES drop merging loading on CryoTop devices wicking method prior plunging into liquid nitrogen. Warming was performed (TS) or All cycles utilized ICSI excluded testicular sperm samples. Survival, fertilization blastocyst development between two groups. Data analyzed utilizing Fisher’s Exact Test. Main results role chance Oocyte differed timing treatments, TS yielding higher (96.1%) than secondsTS (92.0%), p < 0.002. No differences (78.3.0% vs. 79.0%) orin good quality conversion (≥3BB) day 5 (22.1% 25.1%) by 7 (55.3% 55.7%) apparent. The aneuploidy rate blastocysts similar, 28.5% treatment group 27.3% group. Limitations, reasons caution examined retrospectively sibling splits not utilized. Clinical resulting embryo transfer examined. Wider implications findings These help protocols outcomes. Trial registration number applicable