Advancements in technology have helped doctors and researchers know more about embryos and fertility technology. As more research is conducted, we are starting to come across new practices and terminology in the field.
For instance, studies conducted by Reprogenetics (world’s largest genetic lab), have introduced to the world a new term as well as a potential game-changer in the field of assisted reproductive technologies - Mosaic Embryos.
Classifying MosaicismEmbryos are graded as either euploid (normal) or aneuploid (abnormal) by many labs and fertility clinics.
While euploid embryos are suitable for implantation, aneuploid embryos are not, and there is still no clarity on mosaic embryos. A typical mosaic embryo will have both euploid and aneuploid cells.
Having mosaic embryos meant that the IVF journey ended for many couples before they even could begin.
A majority of experts and fertility clinics either don’t recommend or transfer mosaic embryos as there are increased chances of miscarriage, heightened risk of congenital disability, and lower implantation rates.
The StudiesOnly recently has advanced technology come to the rescue. A Fertility and Sterility study has shown that about one-third of mosaic embryos grew into a healthy baby. Even though it was a small sample size, it does hold out hope.
Another research, using a rhesus macaque, was conducted by scientists from Oregon National Primate Research Center at Oregon Health & Science University, Oregon.
The Shawn L. Chavez, Ph.D. led team gives new hope to people seeking infertility treatment. The study confirms that mosaic embryos can adapt to abnormalities and continue growing, resulting in an increased number of positive IVF outcomes.
Using advanced techniques like time-lapse imaging as well as single-cell sequencing, Dr. Chavez led team was able to identify a unique relationship between two biological processes – blastomere exclusion and cell fragmentation – and mosaicism.
The study found that blastomeres and the cell fragments act as embryonic trash bins. During DNA-carrying cell division and/or fragmentation, the embryo was able to identify blastomeres that had genetic abnormalities and stopped them from developing further.
By the time the embryo was implemented into the uterus, these abnormal DNA had already been excluded from the embryo.
This means that imperfect IVF embryos can also be used for transferring and can develop in utero.
How Will it Impact The IVF processAccording to doctors, this discovery is significant as it can spread the joy of being parents in couples having infertility issues.
While selecting embryos, preference is given a normal chromosome complement, but this does not guarantee pregnancy success. For patients who have only mosaic embryos, these finding does give hope that in a few cases, these embryos can result in healthy pregnancies.
Ongoing research plan on using live-cell time-lapse imaging for having a better understanding of the relationship between aneuploidy, blastomere exclusion, and cell fragmentation within the embryo.
Results of this, scientists believe, will open new avenues that could test mosaic human embryo.