Objective: In our previous report in 2016, we achieved 100% post-warmed survival rate for all cleavage stage embryos vitrified using the Cyrotec Method. Cryotec is an innovative method of vitrification to preserve oocytes and embryos of any developmental stage. Here in this study, we further demonstrate the efficacy of the Cryotec Method through analysis of a greater sample size, establishing the validity of the earlier findings.

Materials and methods: A total of 111 Day 3 cleavage stage embryos with 897 blastomeres underwent cryopreservation by vitrification and subsequently warmed for FET cycles using Cryotec Vitrification and Warming Media since we commenced Cryotec Method from July 2013 until now (April 2017) in Alpha Fertility Centre. The study consists of 57 cases with patients in the age range of 18 to 44 with a mean age of 35.3. Practitioner techniques for vitrification and warming were adhered to manufacturers outlined SOPs (Cryotech, Japan). All embryos ranged from 5 cells to 14 cells with <15% fragmentation and were derived from either intracytoplasmic sperm injection or in-vitro fertilization. The survivability of embryos and its blastomeres were assessed in terms of the number of intact or lysed cells upon warming.

Results: After Cryotec warming, all 111 embryos survived with no degradation in quality, yielding 100% post-warmed embryo survival rate. Furthermore, the blastomere survival rate also achieved 100%, indicated by the 897 healthy and intact blastomeres and the absence of lysed cells upon observation. The survivability of embryos was not affected by the number of cells nor degree of fragmentation.

Conclusion: This study validates that the use of Cryotec Method for embryo vitrification and warming consistently achieved 100% post-warmed survival rates in Day 3 cleavage stage embryos and blastomeres in Alpha Fertility Centre. The Cryotec method realizes the total potential of embryo cryopreservation and proves to be superior compared to other vitrification methods practiced in ART laboratories worldwide today.