We analyze 2004 embryo thawing cycles to compare embryo survival, transfer, gestation and implantation rates. MATERIALS AND METHODS: Exceeding embryos scored ≥7 were freezed on
day 2, 3 or 4, the rest freezed if reached blastocyst stage. Only evolutive embryos after 24 hours
from thawing were transferred. RESULTS: 67 cycles were thawed, 12 day2, 37 day3, 5 day4, and 13
Blastocyst.
Surviving rates: 53,6% day 2; 30,2% day 3; 16,6% day 4 and 19% day 5-6. Pregnancy rates: 0% day2; 20% day 3; 50% day 4 and 0% day 5-6. Implantation rates: 0% day 2; 11% day 3; 25% day 4 and 0% day 5-6. CONCLUSIONS: Poor results are found with blastocysts, probably because of their procedence. Day 3 and 4 groups had the best pregnancy and implantation rates, their blastomeres have better evolution and implantation potential after thawing.
