The developmental potential of frozen-thawed hamster preimplantation embryos following embryo transfer: Viability of slowly frozen embryos following slow and rapid thawing

Hamster preimplantation embryos were slowly frozen (0.33°C/min) and seeded above 10°C in TC-199 containing 1.5 M-DMSO. These embryos were thawed either slowly (1.5°C/min) or rapidly (90°C/min). The thawed embryos were examined by morphology, trypan blue exclusion and viability after embryo transfer. Slow thawing gave significantly higher viability compared to rapid thawing. The early preimplantation embryos demonstrate higher sensitivity to freezing. The three tests of viability (morphology, trypan blue exclusion and embryo transfer) were found to be positively correlated.