Vitrification of human embryos subjected to blastomere biopsy for pre-implantation genetic screening produces higher survival and pregnancy rates than slow freezing

Abstract

Purpose Cryopreservation of blastocysts, especially those subjected to the trauma due to blastomere biopsy for the purposes of pre-implantation genetic screening (PGS), requires significant optimization. Laboratory and clinical outcomes were compared to determine the effect of two different cryopreservation techniques on the development of human pre-implantation embryos that underwent blastomere biopsy and blastocoel drainage prior to cryopreservation. Design Retrospective clinical study. Patient(s) Women who requested cryotransfer of supernumerary blastocysts were analyzed by FISH. Results The main outcome measures were post-thaw survival (SR), pregnancy (PR), and implantation (IR). The SR of slowly frozen blastocysts was 83% compared to 97% for vitrified blastocysts. In 160 cases where biopsied embryos were cryotransferred, the results for slowly frozen versus vitrified blastocysts were: SR (71% vs. 95%), PR (23% vs. 37%), and IR (26% vs. 36%, P<0.05), respectively. Conclusion The results revealed that vitrified blastocysts provided higher SR, PR and IR as compared to slowly frozen counterparts.

Genetic Considerations in Recurrent Pregnancy Loss

“…Time-consuming (.24 h) genetic analytics preclude the ability to transfer fresh embryos because testing results are not available to direct selection of embryos for transfer. Advances in embryo cryopreservation and the resultant switch from less efficient slow-freeze methods to ultrafast vitrification have dramatically improved embryo survival rates and clinical post-thaw pregnancy rates Keskintepe et al 2009). Embryo cryopreservation now allows a nearly unlimited window for genetic testing to occur without concomitant decreases in clinical pregnancy and implantation rates (Keskintepe et al 2009).…”

“…Advances in embryo cryopreservation and the resultant switch from less efficient slow-freeze methods to ultrafast vitrification have dramatically improved embryo survival rates and clinical post-thaw pregnancy rates Keskintepe et al 2009). Embryo cryopreservation now allows a nearly unlimited window for genetic testing to occur without concomitant decreases in clinical pregnancy and implantation rates (Keskintepe et al 2009). Efficient and effective new molecular diagnostic tools continue to be developed at a very rapid pace.…”

Cryopreservation of Embryos and Gametes: Past, Present, and Future

“…bifurcated movement to karyotype embryos through pre-gestational genetic screening and cryopreserve blastocysts rather than their cleavage stage counterparts is advantageous in the identiication of embryo competence and in reducing risk of miscarriage and chromosomal defects [101,102]. This practice is important in that common morphological parameters of blastocyst scoring are not related to chromosomal status [101] and particularly for women of advancing maternal age [103].…”

Preimplantation genetic diagnosis and the biopsy technique: Important considerations

“…Anyway, recent data have shown that embryo vitrification provides higher survival rates than conventional slow freezing [36].…”