Journal article

The influence of prefreeze growth rate and blastomere number on cryosurvival and subsequent implantation of human embryos

DH Edgar, H Jericho, H Bourne, JC McBain

JOURNAL OF ASSISTED REPRODUCTION AND GENETICS | KLUWER ACADEMIC/PLENUM PUBL | Published : 2001

Abstract

PURPOSE: To determine whether the relatively low implantation rate of cryopreserved Day 2 embryos with only 2 blastomeres can be increased as a consequence of increasing their blastomere content by extending the prefreeze culture time. METHODS: Of a total of 3480 Day 2 embryos studied, 1921 (55.2%) had reached the 4-cell stage by 40 h postinsemination (FAST) and were transferred or cryopreserved. The remaining embryos that underwent subsequent cell division by 46 h (INTERMEDIATE; 18.3% of total) or 66 h (SLOW; 20.3% of total) were also cryopreserved whereas the 6.2% that remained arrested at 66 h were discarded. Thawed embryos from each category were assessed for survival, post-thaw cleavage..

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