An embryo cleavage pattern based on the relative blastomere size as a function of cell number for predicting implantation outcome

The embryo's cleavage pattern provides valuable supplementary information to the standard evaluation for selecting embryos by cleavage rate and fragmentation, enhancing the likelihood for successful implantation.

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Roee Sela, D.V.M., Liat Samuelov, M.D., Benny Almog, M.D., Tamar Schwartz, B.Sc., Tania Cohen, M.Sc., Ami Amit, M.D., Foad Azem, M.D., Dalit Ben-Yosef, Ph.D.

Vol 98, Issue 3, Pages 650-656.e4



To analyze whether the cleavage pattern redefined for all cleavage stages according to the relative blastomere size as a function of cell number has an additive value in predicting implantation potential of day 2-3 embryos.


Retrospective analysis of standard embryo morphological parameters (cleavage rate and degree of fragmentation) supplemented by cleavage pattern findings of 347 implanted embryos compared to those of a matched control group of 307 embryos that failed to implant.


University-based tertiary medical center.


Two hundred and nine women with successful implantation and 181 controls matched for age and demographic parameters with failed implantation.


In vitro fertilization (IVF), embryo assessment, and embryo transfer

Main Outcome Measures:

Determination of cleavage patterns in synchronized and unsynchronized cleaving embryos and correlations to implantation outcomes.


Significantly more embryos of the implanted group were of good cleavage pattern compared to the non-implanted group (88% vs. 70%; P70%) when the cleavage pattern was assessed on both days 2 & 3.


When combined with measurements of the cleavage rate and degree of fragmentation, the cleavage pattern refines our ability to predict the likelihood of implantation, representing a definitive tool in the selection of top-quality embryos.

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Fertility and Sterility

Editorial Office, American Society for Reproductive Medicine

Fertility and Sterility┬« is an international journal for obstetricians, gynecologists, reproductive endocrinologists, urologists, basic scientists and others who treat and investigate problems of infertility and human reproductive disorders.