Debate 4: Morphological Assessment of Embryos is Outdated
Authors: Chang Tiencheng Arthur , Gardner David K. 
Published: January 2024

Motion: For

The Outdated Significance of Morphological Assessment in Embryo Selection and the Rise of Advanced Technologies in Reproductive Medicine

This symposium lecture presents a compelling debate, shedding light on the diminishing relevance of traditional static morphological assessment as a primary criterion for embryo. The speaker aims to challenge the long-standing reliance on morphological evaluation and advocate for the integration of cutting-edge technologies as a more reliable and objective means of embryo quality assessment. During the debate, the speaker will examine the limitations of morphological assessment, acknowledging its subjective nature, potential bias, and lack of comprehensive insight into embryonic development. The traditional morphological assessment based solely on visual appearance may not adequately predict an embryo’s true potential for successful implantation and healthy pregnancy. A variety of available new technologies will be highlighted during the lecture, showcasing alternatives to morphological embryo assessment. Attendees will gain insight into how these innovative methods can offer more objective and precise measures of embryo quality, enhancing the success rates of assisted reproductive procedures.

The symposium will foster an engaging environment, encouraging active participation and thoughtful discussions among attendees from the reproductive medicine community. Participants will have the opportunity to challenge prevailing notions and explore the implications of adopting new technologies in clinical practice. In summary, this debate aims to catalyze a paradigm shift in embryo evaluation, emphasizing the need to move beyond traditional morphological assessment towards embracing advanced technologies, to optimize embryo selection and lead to improved outcomes in IVF.

Motion: Against

Morphological Assessment of Embryos is Not Outdated

In the era of new technologies and artificial intelligence, looking good has never been more important! On-time progression through specific events is requisite for human preimplantation development and provides important visual insights into the health and physiology of the embryo.

The formation of 2 distinct pronuclei, the times and patterns of cleavage, and how the cells compact are all key markers of development. Following compaction, the formation of the blastocyst is not only a temporally regulated event, but also an energetically demanding process, one that reflects the metabolic activity (a biomarker of viability) of the embryo. Further, at the blastocyst stage it is possible to visualise and quantitate the formation of both the inner cell mass (ICM) and trophectoderm, with all parameters of blastocyst development linked to transfer outcomes.

The development of time-lapse incubation, which can be described as embryo morphology over time, has led to the incorporation of several key morphological features to support embryo selection, further reflecting the significance of embryo morphology. Interestingly, AI algorithms used for embryo selection reflect predominantly those morphological parameters that are known to affect transfer outcomes, such as blastocyst quality.

While only specific molecular tests can accurately determine the precise chromosomal composition of an embryo, key morphological features and events can also be used to tag those embryos at greatest risk of being genetically abnormal.

In conclusion, key morphological developmental events indirectly inform us of the physiology of the embryo (degree of blastocyst expansion reflects metabolic activity for example), and hence this is why morphological grading systems (such as the Gardner Grade for blastocysts) have been shown to be effective in embryo selection for over the past 25 years, and further have proven to be as useful as AI or biomarker analysis for the majority of patients.