The outcomes of human blastocyst cryopreservation: vitrification using cryoloop versus slow-freezing method

摘要

Objective: To compare the outcomes of vitrification using cryoloop with slow-freezing method for human blastocyst cryopreservation.Methods: In IVF-ET cycles, supernumerary embryos were cultured to Day 5 or Day 6, blastocysts were cryopreserved by vitrification using cryoloops or slow-freezing method, then blastocyst survival rate and pregnant rate were compared.Results: 115 vitrified blastocysts from 39 cycles were warmed, 104(90.4%) blastocysts survived. After the transfer of 74 blastocysts in 38 cycles, 28(73.7%) women got clinically pregnant, 2(7.1%) of them suffered from miscarriage, 2 healthy babies were born in 2 deliveries, and the other 24 pregnancies are ongoing. As to slow-freezing method, 87 blastocysts from 21 cycles were thawed, 37(42.5%)of them survived, 28 blastocysts were transferred in 15 cycles, 6(40%) women got clinically pregnant, 1 of them miscarried, 3 healthy babies were born in 2 deliveries, and the other 3 pregnancies are ongoing.Conclusion: The survival rate and pregnant rate of vitrification using cryoloop are superior to traditional slow-freezing method, and the transfer cancel rate is lower than that of slow-freezing method. The miscarriage rate is similar in two methods.