O-240 Embryo assessment: the Istanbul consensus revised
G Coticchio, A Ahlström, G Arroyo, B Balaban, A Campbell, M J De Los Santos Molina, T Ebner, D Gardner, B Kovacic, K Lundin, C Magli, S Mcheik, D Morbeck, L Rienzi, I Sfontouris, N Vermeulen, M AlikaniAbstract
Study question
What are the current recommended criteria for morphological assessment of oocytes, zygotes and embryos?
Summary answer
The present ESHRE/Alpha Scientists in Reproductive Medicine consensus document provides several novel recommendations to assess oocyte and embryo morphology and rank embryos for transfer.
What is known already
A previous Alpha Scientists in Reproductive Medicine / ESHRE consensus on oocyte and embryo morphological assessment was published in 2011. After more than a decade, a thorough review and update was needed.
Study design, size, duration
A working group consisting of Alpha Scientists in Reproductive Medicine executive board members and ESHRE Special interest group of Embryology members formulated recommendations on oocyte and embryo morphological assessment.
Participants/materials, setting, methods
The working group included 17 internationally recognized experts with extensive experience in clinical embryology. Seven members represented Alpha Scientists in Reproductive Medicine and 8 members represented ESHRE, in addition to two methodological experts from the ESHRE central office. Based on a systematic literature search and discussion of existing evidence, the recommendations of the Istanbul Consensus (2011) were reassessed and, where appropriate, updated based on consensus within the working group. After stakeholder review, the final version will be approved by the working group, the Alpha executive board and the ESHRE Executive Committee.
Main results and the role of chance
This updated consensus paper provides 20 recommendations focused on the timeline of preimplantation developmental events and morphological criteria for oocyte, zygote, and embryo assessment. Based on duration of embryo culture, recommendations are given on the frequency and timing of assessments to ensure safety and effectiveness.
Limitations, reasons for caution
Several criteria relevant to oocyte and embryo morphology have not been well studied, leading to either a recommendation against their use for grading or for use in ranking rather than grading. Future updates may require further revision of these recommendations.
Wider implications of the findings
This document provides embryologists with clear advice on best practices when assessing oocyte and embryo quality based on the most recent evidence.