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


METHODS
Retrospective clinical study.


METHODS
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.


CONCLUSIONS
The results revealed that vitrified blastocysts provided higher SR, PR and IR as compared to slowly frozen counterparts.
Keskintepe
Levent
L
Sher Institute for Reproductive Medicine, Las Vegas, USA. leventk@sherinstitute.com
Sher
Geoffrey
G
Machnicka
Anna
A
Tortoriello
Drew
D
Bayrak
Aykut
A
Fisch
Jeffrey
J
Agca
Yuksel
Y
D000328:Adult; D001755:Blastocyst / Q000502:physiology*; D015925:Cryopreservation / Q000379:methods*; D047108:Embryonic Development / Q000502:physiology*; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D005820:Genetic Testing; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D011247:Pregnancy; D012189:Retrospective Studies