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Updated: Jun 4, 2026
Morphometric Protocol for the Objective Assessment of Blastocyst Behavior During Vitrification and Warming Steps
Published on: February 28, 2019
Morphological embryo assessment: reevaluation
Haggai Bar-Yoseph1, Amalia Levy, Yael Sonin
1Fertility and IVF Unit, Department of Obstetrics/Gynecology, Soroka University Medical Center, Beer Sheva, Israel.
Objective:
To assess whether the pronuclear score and embryo nuclear scoring have an additive value to day 2 morphology criteria in the prediction of the implantation rate (IR).
Design:
Retrospective clinical study.
Setting:
IVF Unit, Soroka University Medical Center.
Patient(S):
Analysis of all homogenous IVF fresh embryo transfers from 2008-2010.
Intervention(S):
Morphological evaluation of pronuclear scoring, embryo nuclear scoring, and day 2 embryo morphology scoring on embryos obtained from IVF or intracytoplasmic sperm injection (ICSI) cycles.
Main Outcome Measure(S):
Implantation rate of homogeneous transfers.
Result(S):
No statistical association was found between the pronuclear scoring system (Z) and IR. The pronuclear score Z3 had a significantly better performance than Z1, Z2, and Z4 (IR = 25.2%, 22%, 21.4%, and 11.8%, respectively). Assessment of the second day embryo morphology scoring (index [IDX]) was found to associate with IR. IDX1, IDX2, IDX3, IDX4, and IDX5 had an IR of 36.1%, 28%, 21.9%, 14.2%, and 0, respectively. The nuclear scoring including: 1 nucleus in all blastomeres, 1 nucleus in part of the blastomeres, no visualization, and multinucleation showed high association with IR = 32.7%, 22.9%, 14.8%, and 9.1%, respectively. The effect of the nuclear scoring on IR was lost in a multivariable analysis that included day 2 embryo morphology scoring.
Conclusion(S):
Our results suggest that there is no additive value in grading the zygote on day 1 or embryo nuclear scoring on day 2 to day 2 embryo morphology for the prediction of IR.
