Knowledge of Egg Freezing

 

◉ Most studies show that the quality of embryos is not affected by the duration of cryopreservation. Prolonged cryopreservation of human embryos does not affect pregnancy outcome.

◉ No significant difference in vitrification cryosurvival between immature GV and mature M-II stage.

◉ Fertilization rates of thawed oocytes were also comparable to those of fresh autologous intracytoplasmic sperm injection cycles (70% vs. 72%).

◉ The implantation rate per embryo (43% vs. 35%) and the clinical pregnancy rate per transfer (57% vs. 44%) of vitrified cryopreserved oocytes were significantly higher than that of embryo implantation with fresh oocytes. However, there was no statistically significant difference in live birth/continued pregnancy rates (39% vs. 35%).

◉ Each frozen egg thawed and implanted has a live birth rate of about 6.41 TP3T.

◉ Treatment with autologous oocyte vitrification cryoheating is as effective as cycles with fresh oocytes.

◉ Only 441 TP3T of thawed MI stage eggs will mature to MII stage, and only 41 TP3T of thawed GV stage eggs will mature to MII stage.

 

 https://www.fertstert.org/article/S0015-0282(15)02037-3/fulltext

 

◉ Most studies dicate that the quality of embryos is not influenced by the duration during cryo-storage. 

 

◉ Long-term cryo-storage of human embryos did not affect the pregnancy outcome. 

 

◉ There is no significant difference in the survival rate between oocytes vitrified at the immature GV stage and those vitrified at the mature M-II stage. 

 

◉ Postthaw oocyte fertilization rates were also comparable to fresh autologous intracytoplasmic sperm injection cycles (70% vs. 72%). 

 

◉ Implantation rates per embryo transferred (43% vs. 35%) and clinical pregnancy rates per transfer (57% vs. 44%) were significantly higher with vitrified-warmed compared with fresh oocytes. 

 

◉ However, there was no statistically significant difference in live birth/ongoing pregnancy (39% vs. 35%). 

 

◉ The overall vitrified-warmed oocyte to live born child efficiency was 6.4%.

 

◉ Treatment outcomes using autologous oocyte vitrification and warming are as good as cycles using fresh oocytes. 

 

◉ only 44% of the oocytes vitrified at the MI stage subsequently matured to the MII stage in vitro after warming, and only 4% of the oocytes vitrified at the GV stage did so.