Clinical significance of intercellular contact at the four cell stage of human embryos and the use of abnormal cleavage patterns to identify embryos with low implantation potential A time lapse study

Capsule:
Reduced intercellular contact in four-cell stage human embryos leads to compromised subsequent development and implantation potential. Implantation rates could be improved by not selecting embryos showing abnormal cleavage patterns.

Authors:
Yanhe Liu, M.Sc., Vincent Chapple, M.B., B.S., F.R.A.N.Z.C.O.G., Katie Feenan, M.Sc., Peter Roberts, Ph.D., Phillip Matson, Ph.D.

Volume 103, Issue 6, Pages 1485-1491

Abstract:

Objective:
To investigate the clinical significance of intercellular contact point (ICCP) in four-cell stage human embryos and the effectiveness of morphology and abnormal cleavage patterns in identifying embryos with low implantation potential.

Design:
Retrospective cohort study.

Setting:
Private IVF center.

Patient(s):
A total of 223 consecutive IVF and intracytoplasmic sperm injection treatment cycles, with all resulting embryos cultured in the Embryoscope, and a subset of 207 cycles analyzed for ICCP number where good-quality four-cell embryos were available on day 2 (n = 373 IVF and n = 392 intracytoplasmic sperm injection embryos).

Intervention(s):
None.

Main Outcome Measure(s):
Morphologic score on day 3, embryo morphokinetic parameters, incidence of abnormal biological events, and known implantation results.

Result(s):
Of 765 good-quality four-cell embryos, 89 (11.6%) failed to achieve six ICCPs; 166 of 765 (21.7%) initially had fewer than six ICCPs but were able to establish six ICCPs before subsequent division. Embryos with fewer than six ICCPs at the end of four-cell stage had a lower implantation rate (5.0% vs. 38.5%), with lower embryology performance in both conventional and morphokinetic assessments, compared with embryos achieving six ICCPs by the end of four-cell stage. Deselecting embryos with poor morphology, direct cleavage, reverse cleavage, and fewer than six ICCPs at the four-cell stage led to a significantly improved implantation rate (33.6% vs. 22.4%).

Conclusion(s):
Embryos with fewer than six ICCPs at the end of the four-cell stage show compromised subsequent development and reduced implantation potential. Deselection of embryos with poor morphology and abnormal cleavage revealed via time-lapse imaging could provide the basis of a qualitative algorithm for embryo selection.

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