Navigating Choices: Mosaic Embryos
A matter of choice? – patient decision-making and support in non-euploid embryo transfers. Human Fertility, 27(1). Viñals Gonzalez, X., Akompey, K., Sen Gupta, S., & Nicholls, J. (2024).
A global survey of 111 individuals who underwent IVF with preimplantation genetic testing (PGT-A) found that transferring embryos with chromosomal mosaicism is emotionally complex and often under-supported. Key factors influencing decision-making include thorough discussions with clinicians, clarity during consultations, and local treatment practices. Major challenges experienced were mismatched expectations, inadequate information, and feeling unsupported, highlighting the need for patient-centred communication and proactive clinic support.
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When embryos are tested during IVF using PGT-A, a few cells are biopsied and analysed to check for chromosomal abnormalities. Think of your genetic material as books on a shelf: PGT-A doesn’t read the books for typos, it just counts them. Missing or extra books mean the embryo may have compromised developmental potential.
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Embryos are made of cells. These cells can be genetically normal (euploid) or abnormal (aneuploid). Mosaicism in embryos means some cells have the correct genetic make up while others don’t, creating a mix within the same embryo.
Why does this research matter?
For individuals, understanding the potential and implications of mosaic embryos can eliminate fear and give you control. Inadequate counselling often pushes individuals to self-research.
For professionals, transparent counselling and evidence-based guidance aren’t optional. You ought to bridge the gap between individual expectations and technical limitations. Provide clear, timely, and emotionally supportive counseling to aid decision-making.
“I wish PGT-A was explained as not an exact science.”
The study surveyed individuals who faced the choice of transferring embryos that showed mixed normal and abnormal chromosomes. Many felt they didn’t receive enough details from clinics: what the outcomes might be, how likely it is to succeed, and what risks exist. This led most to self-research and self-advocacy. When clinics did engage—by explaining what mosaicism means, discussing risks directly, and going over what non-normal embryo transfer entails—patients felt far more supported and informed.
“An overview of PGT-A was provided, but no information on the incidence of mosaicism and the potential outcomes of transferring a mosaic.”
In detail… The researchers used logistic regression to identify what factors most impacted patients’ confidence in reproductive decision-making. The key predictor was whether the clinic offered the opportunity to discuss test result implications (OR 3.98). Other topics—mosaicism, embryo risk, and potential embryo use—also correlated significantly. Patients treated in the USA were less likely to feel informed (OR 0.218), hinting at possible systemic differences. The qualitative thematic analysis revealed critical gaps: unrealistic expectations, insufficient information, and a lack of an empowered decision path. Clinics appear to be communicating PGT-A as definitive rather than probabilistic, failing to explain technical uncertainties, and unintentionally placing emotional labour on patients.
Practical Takeaways
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Does my clinic report mosaicism?
What does it mean for my embryo?
What are the risks and success rates?
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Genetic counselling, peer-reviewed publications, reliable organisations e.g. charities; to supplement clinic information.
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Reflect on how well you've been supported—did the clinic invite your questions?
Consider a second opinion if your care team is reluctant to discuss or transfer mosaic embryos.
