Squeezable IVF embryos
Is squishiness of IVF embryos indicative of their viability? In other words, are squeezable embryos the most viable among others? This is the question that a research team from Stanford University has addressed.
The idea for this study objective originated from an anecdotal tip from the director of Stanford’s IVF lab, Barry Behr, that some oocytes are squishier than others. Holding to that, researchers decided to investigate whether this event was somehow associated with the embryos’ potential to develop normally.
Scientists of Stanford University (comprised of both bioengineers and physicians) carried out their first experiments working with mice. The results have been published in nature communications. They fertilized mouse eggs and measured their rigidity after one hour. The researchers found that measuring rigidity could actually predict the fertilized eggs’ viability more accurately and at an earlier stage of development compared to conventional embryo screening methods.
Current methods for embryo selection are based on invasive and non-invasive procedures with different pros and cons that could affect the embryo transfer into the uterus. Non invasive techniques, like time lapse microscopy, analyse embryo morphology after culturing them in stable conditions for up to 6 days, choosing the best, viable embryos, in terms of morphology and cell dividing rate for increasing chances of successful implantation.
Invasive techniques use a few embryo cells at the stage of blastocyst, offering a preimplantation genetic diagnosis that could increase implantation rates by choosing embryos with less genome abnormalities. However, invasive techniques are always a matter of debate concerning the implications and safety of embryonic manipulation.
But, invasive or non-invasive, current methods are not as accurate as needed for fertility experts to feel confident on their embryo selection, pushing them into transferring multiple embryos with the hope that at least one of them will lead to live birth.
Scientists continued their research with fertilized human oocytes, concluding the same as with mice. More specifically, they reported that the rigidity assessment has 90% accuracy in predicting an embryo’s likelihood to reach a healthy blastocyst stage. They are looking forward to test viability in patients, proving the methods clinical potential in selecting the best embryos; lowering the risk of multiple gestation and the high cost of current methods.