EGG DONATION: IS IT INDISTINCT TO USE FRESH OR THAWED OOCYTES?

Abstract

To compare embryonic development and clinical outcomes between egg donation treatments with fresh oocytes and with thawed oocytes. The results from 337 egg donation patients were compared: 192 received fresh oocytes and 145 received thawed oocytes. Thawed oocytes belonged to same donors and cohorts as the fresh. Embryos were cultured in Global Total LP medium (Life Global) until blastocyst stage. Fertilization rate, post ICSI lysis rate, evolving embryos (transferred + cryopreserved) rate, blastulation rate, percentage of top-quality blastocysts, pregnancy rate, cumulative pregnancy rate, and cancellation rate were compared between groups. Parametric and non-parametric Analysis of Variance (ANOVA) were performed in order to compare quantitative parameters, as appropriate. Qualitative parameters were compared by frequency analysis, using contingency tables. P-values ˂0,05 were considered significant. When comparing the results between fresh oocyte recipients and thawed oocyte recipients, all the parameters had statistically significant differences in favor of the fresh oocytes group, with the exception of pregnancy and cumulative pregnancy rates, in which no significant differences were found. Fresh oocyte recipients had lower lysis and cancellation rates, while their fertilization, blastulation, evolving embryos, pregnancy, and cumulative pregnancy rates, and percetage of top-quality blastocysts, were higher.Tabled 1FRESHTHAWEDp-valuen192145Survival rate88,35%Oocyte average6,29 (4-10)6,88 (4-11)Post ICSI lysis rate1,65%4,76%0,0004Fertilization rate88,01%72,81%˂0,0001Blastulation rate69,65%57,01%0,0001Evolving embryo rate53,91%38,11%˂0,0001Percentage of top-quality blastocysts42,16%23,83%˂0,0001Pregnancy rate46,28%35,65%0,0972Cumulative pregnancy rate41,73%36,77%0,3204Cancelation rate2,75%9,85%0,0120 Open table in a new tab Despite not significant differences were found in pregnancy and cumulative pregnancy rates between both groups, egg donation procedures with fresh oocytes present better results, both clinical and biological. This is mainly evidenced in the higher percentage of top-quality blastocysts, which gives to these patients the possibility of cryopreserve surplus embryos for further transfers. It would be convenient to reevaluate the cumulative pregnancy rate to clarify whether, having transferred all the embryos, significant differences are found between the groups.