The Istanbul Consensus update: a revised ESHRE/ALPHA consensus on oocyte and embryo static and dynamic morphological...

Area of Science:

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

Background:

• The European Society of Human Reproduction and Embryology (ESHRE)/Alpha Scientists in Reproductive Medicine (ALPHA) previously published consensus recommendations in 2011.
• Advancements in time-lapse technology necessitate an update to oocyte and embryo morphological assessment guidelines.

Purpose of the Study:

• To provide updated recommendations for assessing oocyte and embryo morphology.
• To establish criteria for ranking embryos for transfer based on morphology and developmental timelines.
• To integrate current evidence and time-lapse technology into best practices for clinical embryology.

Main Methods:

• A working group of 17 international experts from ALPHA and ESHRE formulated recommendations.
• Systematic literature search and discussion of existing evidence informed the update.
• Reassessment and revision of the 2011 Istanbul Consensus recommendations based on new data.

Main Results:

• The consensus document presents 20 updated recommendations for oocyte, zygote, and embryo assessment.
• Recommendations focus on preimplantation developmental timelines and morphological criteria.
• Guidance is provided on the frequency and timing of assessments during embryo culture.

Conclusions:

• The updated guidelines offer best practices for embryologists in assessing oocyte and embryo quality.
• Some morphological criteria are recommended against for grading due to insufficient evidence, while others are suggested for ranking.
• This document aims to enhance consistency and effectiveness in embryo assessment and selection for transfer.