embryo grading
A standardized system for assessing embryo quality based on morphological characteristics to guide selection for transfer.
Full Definition
Embryo grading is a morphological assessment system used by embryologists to evaluate embryo quality and predict implantation potential. For cleavage-stage embryos, grading considers cell number, symmetry, and fragmentation. For blastocysts, the system evaluates the inner cell mass, trophectoderm, and degree of expansion using standardized scales (typically AA, AB, BA, BB, etc.). While embryo grading is subjective and doesn't guarantee success, it serves as an important tool for embryo selection and counseling patients about treatment outcomes. Time-lapse imaging systems are increasingly supplementing traditional grading methods.
Usage
Usage note: Not capitalized unless beginning a sentence; grading systems may use letters and numbers.
In Context
- "The embryologist assigned a grade of 4AA to the highest quality blastocyst." — Laboratory report
- "Embryo grading protocols may vary between laboratories but follow similar principles." — Quality assurance document