Warming Oocytes with a Universal Warming Medium and Protocol is as Good as the Company Media and Protocols

Background: A universal warming media and protocol would simplify exchange and use of oocytes and embryos between different IVF centres. Aim: The aim of this study was to compare a universal warming medium and protocol (Parmegiani et al, 2014 RBMonline 28, 614-23) with 3 other warming media and protocols which were used with their corresponding vitrification media (2 commercial, one in house) measuring survival (pre and post insemination combined), fertilization and blastocyst rate. Method: This was a prospective study on 300 mature cumulus-free F1 mouse oocytes divided between three vitrification protocols, SAGE™ vitrification (S), RapidVit™ Omni by Vitrolife (V), and the in house ‘MCE-Trehalose’ (M) designed for mouse embryos. Oocytes for each vitrification group (S,V & M) were divided equally to be warmed either by the corresponding warming protocols (S/S, V/V & M/M and or the universal warming protocol (S/U, V/U and M/U). Surviving oocytes were inseminated in vitro with 250,000 motile sperm/ml 2h after warming (18 oocytes were not retrieved post-warm). Results: V/V (25%), V/U (42%) had significantly lower survival than all other groups S/S (72%), S/U (76%), M/M (91%), M/U (82%; P