IFFS/JSRM International Meeting 2015(2015.4.26-29 Yokohama）
What is the most important factor associated with development after thawing on late morulas frozen at day5?
Osaka New ART Clinic
New ART research center
To investigate developing late morulas that frozen at day5 and the factor of associated with late morulas.
DESIGN: Retrospective study.
Materials and Methods
We investigated late morulas which were frozen at day5 in our clinic from January 2010 to June 2014. All morulas were cultured for 20-26 hours after thawing. These embryos were divided two groups according to their formed blastocele and reached blastocysts (Formed group, n=94) or unformed blastocele (Unformed group, n=30). Furthermore, each groups were compared by female age, IVF number, compaction grade (grade1-3), fragmentation rate (%), blastomere number at day3 and extent of forming compaction at day4 (unformed compaction; 0, partial compaction; 0.5, full compaction; 1).
There were no significant differences between Formed group and Unformed group with female age (36.5 versus 37.9, P=0.08), IVF number (3.07versus 3.77, P=0.11), compaction grade (1.95versus 1.73, P=0.09), fragmentation rate (9.57versus 8.00, P=0.27) and blastomere number at day3 (7.72versus 8.07, P=0.39). However, there was a significant difference in morphology at day4, the rate of compaction at day4 was higher in Unformed group (0.43 versus 0.68, P=0.003).
When late morulas frozen at day5 had already widely formed compaction at day4, they were high possibility of development arrest after thawing.