The question of how much genetic information is useful in an IVF cycle remains one of the more contested areas in reproductive medicine. Whole-genome embryo screening sits at the centre of that debate, generating significant scientific interest, considerable public commentary, and genuine uncertainty about its role in clinical practice.
A study published in Nature Medicine (Kumar et al., 2022) has been central to that ongoing discussion. It examined whether whole-genome risk prediction across 12 common conditions was technically feasible in preimplantation embryos. The study demonstrated high genotype accuracy across conditions. The question of whether that accuracy translates into clinical utility is one the authors themselves leave open, and one that professional guidance continues to address.
What the Study Did
The research, conducted by a team at MyOme and Natera, recruited 10 couples who had previously undergone IVF. Both parents had their full genomes sequenced, and 110 embryos from those cycles were genotyped. Using a method called whole-genome reconstruction (WGR), the researchers computationally predicted each embryo's inherited genome and used those predictions to calculate polygenic risk scores across 12 conditions, including cancers, cardiometabolic diseases, and autoimmune conditions.
The accuracy of those predictions was then verified by comparing the reconstructed embryo genomes against DNA samples from the children who were actually born from those cycles. Genotype accuracy at sites relevant to polygenic risk scoring ranged from 97.2% to 99.4%, depending on the stage at which the embryo biopsy was taken.
The Most Significant Finding
The most clinically striking result came from one specific family. The mother carried a pathogenic BRCA1 variant, a known high-penetrance mutation significantly elevating breast cancer risk. Of the family's 20 viable embryos, 13 carried the pathogenic variant.
When the researchers combined BRCA1 carrier status with each embryo's polygenic risk score for breast cancer, the predicted difference in breast cancer odds across the embryos was 15-fold. Using polygenic risk scoring alone produced a 3-fold difference. Using BRCA1 status alone produced a 4.5-fold difference. The combination was substantially more informative than either approach on its own.
This finding illustrates a specific and important scenario: where a known high-penetrance variant is already in the picture, combining rare variant data with polygenic risk scoring may add meaningful discriminating power that neither method provides alone.
Where the Evidence Becomes More Cautious
Outside of the BRCA1 scenario, the picture is more complex. For the other nine couples in the study, who did not carry a known high-penetrance variant, most embryos showed less than a twofold difference in predicted breast cancer odds between siblings. The paper's discussion section is explicit: the clinical utility of using polygenic risk scores to guide embryo selection in IVF remains to be proven.
The study was also retrospective and preclinical. It did not prospectively guide embryo selection, and it did not measure clinical outcomes for children born from the cycles. The approach is limited to inherited genetic variation and cannot detect de novo mutations, which arise spontaneously and are responsible for a substantial proportion of certain early-onset neurodevelopmental conditions and some chromosomal microdeletion syndromes. Polygenic risk scores also have reduced predictive power in non-European populations, a limitation the authors acknowledge directly.
What the Evidence Consensus Shows
The scientific and clinical consensus on polygenic embryo screening is consistent across multiple professional bodies and independent research groups.
No prospective studies have demonstrated that children born following polygenic embryo screening have better health outcomes than those born without it. The conditions being screened for are diseases of adulthood, influenced as much by environment and lifestyle as by inherited genetic risk, and they take decades to develop. Demonstrating clinical benefit in the way required to justify routine use is genuinely difficult to achieve.
Current polygenic models also have meaningful limitations. Predictive accuracy varies across ancestral backgrounds, with models developed predominantly in European populations performing less reliably in others. Even embryos ranked as higher risk have a high likelihood of developing into healthy adults, and the risk of discarding viable embryos based on predictions that may not materialise is a practical consequence that carries real implications for cumulative live birth rates per IVF cycle.
Major reproductive medicine and genetics bodies have consistently recommended that polygenic embryo screening remain within research settings until prospective evidence of clinical benefit is available. That position reflects the same evidence threshold applied to any clinical intervention.
What This Means for IVF Practice
The debate around whole-genome embryo screening is often framed as a binary question: should it be offered or not? The evidence suggests a more nuanced position is warranted.
For couples undergoing IVF who carry a known pathogenic variant in a high-penetrance gene, expanded genomic analysis that combines rare variant detection with polygenic risk scoring may add genuinely useful information to embryo selection decisions. For couples without a known high-penetrance variant, the clinical benefit of routine polygenic embryo screening across common conditions is not established. The technical capability to generate the information exists. The evidence that acting on that information improves outcomes for children born from those cycles does not.
The practical consequence for patients is also worth noting. Incorporating polygenic risk scoring across multiple conditions into an IVF cycle generates complex, probabilistic information about conditions that may or may not develop over a lifetime, influenced by environmental and lifestyle factors as much as genetic predisposition. Helping patients understand what that information does and does not mean is not straightforward, and the major professional bodies have consistently identified genetic counselling as an essential component of any responsible pathway.
Looking Forward
Research in this area is continuing, and the science of polygenic prediction is improving. As prospective studies accumulate data on outcomes, the role of expanded genomic analysis in IVF will become clearer. The evidence supports a targeted approach: applying expanded genomic tools where there is a specific clinical question they are well-placed to answer, rather than routinely across all IVF cycles.
For clinicians, the most important role remains consistent with what the evidence shows across all areas of genomic medicine: helping patients understand what a test can and cannot tell them, and ensuring that decisions made in the context of an IVF cycle are grounded in evidence rather than driven by the availability of information alone.
Reference:
Kumar, A., Im, K., Banjevic, M. et al. Whole-genome risk prediction of common diseases in human preimplantation embryos. Nat Med 28, 513–516 (2022). https://doi.org/10.1038/s41591-022-01735-0
