P-242 Oocyte morphology before vitrification is associated with the post-warming survival rate

Abstract

Abstract Study question Although oocyte vitrification is efficient for fertility preservation, the information about damage post-warming is limited. Could the oocyte morphology before vitrification predict the survival rate? Summary answer Precisely measuring the oolemma/whole oocyte surface area ratio may predict the post-warming survival rate before performing oocyte vitrification. What is known already Recent studies suggest that oocyte vitrification has higher post-warming survival and pregnancy rates. However, the oocyte post-warming survival rate depends on the oocyte quality but not maternal age. Furthermore, it has been well received that the cell surface/volume ratio is related to the efficiency of cryoprotective additives permeability. Moreover, the oocyte shows a large perivitelline space (PVS) that is negatively related to clinical outcomes. Nevertheless, no studies precisely defined large PVS by measuring the oolemma/whole oocyte surface area ratio. Therefore, we assessed the correlation between the oolemma/whole oocyte surface area ratio and the post-warming survival rate. Study design, size, duration A retrospective study enrolled 43 IVF cycles undergoing oocyte thawing from 2018 to 2020 at Linkou Chang Gung Memorial Hospital. Participants/materials, setting, methods A total of 161 oocytes were warmed. We excluded the oocyte were shipped to our center, MI stages, and without electric medical images. We retrospectively collected all the electric medical images of warmed oocytes that were measured the surface area of oolemma and whole oocyte using ImageJ. Linear regression and Receiver operating characteristic (ROC) curve analysis were performed for further analysis. Main results and the role of chance Our finding showed that the maternal age (38.1 ± 5.3) at oocyte vitrification was not correlated to survival rate (P = 0.26) and the oolemma/whole oocyte surface area ratio (P = 0.59). However, the ROC curve revealed that the oolemma/whole oocyte surface area ratio could predict the survival rate post-warm (AUC: 0.67, 95%CI: 0.56-0.78). Limitations, reasons for caution Small sample size limited the power of this study, and the higher advanced maternal age group involved in this study may not represent the younger group’s outcomes. Therefore, future studies need to enlarge the sample size to evaluate the prediction efficiency of the oolemma/whole oocyte surface area ratio. Wider implications of the findings Our study demonstrates the possible factor related to oocyte cryo-damage. The lower oolemma/whole oocyte surface area ratio represents the oocyte having a larger PVS that has a higher chance of damage after thawing, which shows that by precisely qualified the size of PVS could evaluate the oocyte quality before vitrification. Trial registration number Not applicable