Interobserver agreement and intraobserver reproducibility of embryo quality assessments

BACKGROUND: The objective of this investigation was to determine the inter- and intraobserver agreement when assessing embryo quality. METHODS: This investigation included 4002 cleaved embryos from 7535 oocytes retrieved in 688 patients undergoing IVF cycles in a multicentre trial. Embryos were evaluated locally at the inverted microscope at 28, 44 and 68 h (+/- 1 h) post-insemination. Digital images of the embryos were assessed centrally by three blinded embryologists. To assess reproducibility, 215 randomly selected cleaved embryos from 33 patients were re-evaluated by the three central embryologists. RESULTS: The interobserver agreement among the central embryologists (using the same method of evaluation; 2D images) was good for classification of top-quality embryos (kappa 0.71-0.73), excellent for classification of normally developed embryos (kappa 0.83-0.86) and good-excellent for classification of transferable embryos (kappa 0.78-0.82). The interobserver agreement between local and consolidated central assessment (different methods of evaluation, inverted microscopy versus 2D images) was good for all three embryo classifications (kappa 0.64-0.79). The intraobserver reproducibility for all three overall embryo classifications was excellent for the consolidated central assessment (kappa 0.80-0.91). CONCLUSION: Embryo quality can be determined with a good degree of interobserver agreement independently of the method of evaluation. Embryologists classify embryos with excellent intraobserver reproducibility.