Inter-centre reliability in embryo grading across several IVF clinics is limited: implications for embryo selection

Area of Science:

• Reproductive Medicine
• Embryology
• In Vitro Fertilization (IVF)

Background:

• Accurate embryo grading is crucial for successful in vitro fertilization (IVF) outcomes.
• The Istanbul Consensus provides standardized guidelines for embryo assessment.
• Variability in embryo grading across different IVF clinics can impact treatment efficacy.

Purpose of the Study:

• To assess the intra- and inter-centre reliability of embryo grading based on the Istanbul Consensus.
• To evaluate the impact of interactive training on improving grading consistency.
• To identify areas for enhancing the reliability of embryo selection in IVF.

Main Methods:

• Embryologists from multiple IVF clinics graded Day 3 embryos and blastocysts photographed on three focal planes.
• Study Phase I involved initial grading according to the Istanbul Consensus.
• Study Phase II included interactive training with expert panel grading.
• Study Phase III assessed blinded evaluations post-training to measure reliability improvements using Cohen's kappa.

Main Results:

• Intra-centre reliability was substantial for blastomere symmetry (0.63) and fragmentation (0.72), and moderate for inner cell mass (0.59) and trophectoderm (0.56) quality.
• Initial inter-centre reliability was fair (0.21-0.4) but improved to moderate (0.41-0.6) after interactive training.
• Training enhanced reliability across most parameters, with blastomere fragmentation in senior embryologists already at moderate levels pre-training.

Conclusions:

• Intra-centre embryo grading reliability is generally moderate to substantial, while inter-centre reliability is initially fair.
• Interactive training significantly improves inter-centre reliability, demonstrating its effectiveness in standardizing embryo assessment.
• External quality assessment and artificial intelligence hold potential for further enhancing the reliability of embryo selection in IVF.