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9 June 2025

What Is Embryo Grading and Why Do We Use It?

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Sims IVF

What Is Embryo Grading?

Embryo grading assesses the developmental quality of embryos under lab conditions.

It evaluates:

  • Morphology – shape, structure, and cell features.
  • Developmental timing (morphokinetics) – how fast and precisely an embryo reaches specific developmental checkpoints.

Why Is Embryo Grading Used?

  • Helps reduce the risk of multiple pregnancies by transferring fewer, better-quality embryos.
  • To identify embryos with the highest chance of implantation and live birth.
  • Informs decisions on transferfreezing, biopsy.

What Does It Tell Us?

  • Embryo grading offers insights into:
    • Viability
    • Development potential
    • Transfer readiness
  • It's not diagnostic – a high grade doesn't guarantee success, and lower grades can still result in healthy births.

Day 3 vs Day 5/6 Embryos

FeatureDay 3 (Cleavage Stage)Day 5 (Blastocyst Stage)

Developmental Stage6–10 cells100+ cells, organised structures

Transfer/Frozen UseLess commonPreferred for transfer/freezing

Grading CriteriaCell number, symmetry, fragmentationExpansion, ICM, TE quality

Predictive AccuracyModerateHigher – closer to implantation stage

Gardner Grading System (for Blastocysts)

Widely used for Day 5/6 blastocysts:

  • Expansion Stage (1–6) – degree of blastocoel expansion.
  • Inner Cell Mass (ICM): forms the foetus.
  • Trophectoderm (TE): forms the placenta.

Example:
4AA = Expanded blastocyst (Grade 4) with excellent ICM and TE.

Our Clinic’s Advanced Approach

We use combined grading for the most informed embryo selection:

KidScore™ (Morphokinetic Algorithm)

  • Analyses time-lapse videos of embryo development.
  • Scores based on how closely embryo timing matches ideal patterns.
  • Increases objectivity and reduces inter-operator variability.

iDA Score™ (Vitrolife AI Platform)

  • Uses artificial intelligence to analyse embryo time-lapse images and predict:
    • Implantation potential
    • Embryo ranking
  • Trained on hundreds of thousands of outcomes.
  • Adds a powerful, data-driven layer to traditional grading.

Our system combines morphology + morphokinetics + AI scoring to guide embryo selection with maximum precision.

Key Takeaways

  • Embryo grading is essential in IVF but has evolved with technology.
  • We combine visual assessment, developmental timing, and AI-powered prediction for best outcomes.
  • Our goal: help you achieve a healthy pregnancy, efficiently and safely.

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