The IVF journey introduces many new concepts, including mosaic embryos if you opt for genetic testing. A mosaic embryo contains cells with different genetic makeups. We aim to provide a clearer understanding of how these embryos fit into the larger picture of embryo genetic testing and your IVF journey.
Understanding mosaic embryos can clarify how they fit into the broader scope of genetic testing and your IVF experience.
If you would like to get more free information now about embryos, such as embryos vs. zygotes, then you can learn more here. You can also contact us online if you’re considering surrogacy. We are always here to help.
What Is a Mosaic Embryo?
A mosaic embryo contains a mix of cells:
An embryo with the correct number of chromosomes. An embryo with too many or too few chromosomes.
An embryo is typically classified as mosaic when 20-80% of its cells are abnormal. The degree of mosaicism is key:
20-40% of cells are abnormal. 40-80% of cells are abnormal.
How Are Mosaic Embryos Detected?
Mosaic embryos are identified through preimplantation genetic testing for aneuploidy (PGT-A), which checks for chromosomal abnormalities such as:
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Down syndrome
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Turner syndrome
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Trisomy 13 and 18
During PGT-A, a small sample of cells from the embryo is analyzed. If some but not all cells show abnormal chromosome numbers, the embryo is classified as mosaic.
Is It Safe to Implant a Mosaic Embryo?
Whether it’s safe to implant a mosaic embryo depends on several factors, including:
A higher degree may increase the likelihood of implantation failure. The effects of transferring mosaic embryos are still being researched, so it’s generally recommended to prioritize transferring euploid embryos. Your unique situation plays a role in determining the best course of action.
A genetic counselor or fertility specialist can provide personalized guidance. Some clinics recommend transferring a mosaic embryo only when no euploid embryos are available or suggest trying another IVF cycle.
Success Rates of Mosaic Embryo Transfers
According to a 2019 study by the National Library of Medicine, mosaic embryos resulted in a live birth rate of 46.6%. However, most experts advise prioritizing euploid embryos, which have a much higher success rate. For example, Reproductive Medicine Associates found a live birth rate of 94.9% for euploid embryo transfers.
If you’d like to learn more about embryo transfer success rates or explore surrogacy, contact us online. We're here to help you navigate your fertility journey.