A new study released by Stanford bioengineers and physicians has determined that the correct amount of ‘squishiness’ of an embryo can determine whether it will be successful once implanted.
Selecting the right fertilized embryo for in vitro fertilization (IVF) might be as simple as choosing a ripe piece of fruit: Just give it a squeeze. If it’s too firm or too soft, it might not be good. The sweet spot in between is just right.
In the study, the team measured the rigidity of an hour-old fertilized egg by applying a pipette, and this tenique is being deemed to potentially greatly improve success rates in single-egg IVF.
Formerly, the most promising embryos have been determined by what “looks best”, applying an evaluation that looks at the rate that the cells have been dividing, and the embryo’s overall morphology. This takes place in the days following the egg’s fertilization, until it reaches a blastocyst stage (although many embryos are transferred earlier than that).
Not only does this study greatly affect the number of IVF treatments a woman may have to undergo, and the associated costs with it, but it also has implications that can improve the health of the woman.
“A lot of twins are born because we don’t know which embryos are viable or not, so we transfer several at one time,” said lead-author Livia Yanez, a bioengineering PhD student in David Camarillo’s lab at Stanford. “This can increase the risk of neonatal mortality and cause complications for babies and the mothers.
“We wanted to develop a mechanical test that could ascertain embryo viability well enough that doctors could implant just one embryo and have a very good feeling that it would be viable,” she said.
Stanford has repeated the experiment with the fertilized human eggs and have determined that the rigidity “squishiness” factor could predict whether an embryo reached a healthy blastocyst stage with 90% accuracy.
They will be ramping up to test this viability in patients.