In vitro fertilization is all about picking the best embryos — the ones that are most likely to develop normally. Historically, that's been a hit-or-miss process, hence IVF success rates that are lower than clinicians and patients would like. But now, researchers have found the best way to select embryos may be by squeezing them.
A Stanford press release explains:
A new study by Stanford bioengineers and physicians finds that measuring the rigidity of an hour-old fertilized egg can predict its viability more accurately than current methods at this early stage...
Using a small pipette, the researchers applied a small amount of pressure to mice eggs an hour after fertilization and recorded how much each egg deformed. They placed the embryos in a standard nurturing liquid and reexamined them at the blastocyst stage. At this point, the eggs that had provided a certain range of "push back" were more likely to produce healthy-looking, symmetrical embryos. The researchers built this data into a predictive computer model that, based only on the egg's squishiness, can now predict with 90 percent accuracy whether a fertilized egg will grow into a well-formed blastocyst.
Next, they transferred the embryos to mother mice. Embryos classified as viable based on squishiness were 50 percent more likely to result in a live birth than embryos classified as viable using conventional techniques.
The research, which appears today in Nature Communications, was inspired by an anecdotal tip from Barry Behr, PhD, director of Stanford's IVF laboratory, who noted that embryos vary in consistency. But David Camarillo, PhD, assistant professor of bioengineering and a senior author of the study, said the study's robust results weren't expected.
"Although cancer and other diseases involve stiff tumors or tissues, our colleagues have been surprised that we can gain so much information from this simple little mechanical test," he said in the release. "It is still surprising to think that simply squeezing an embryo the day it was fertilized can tell you if it will survive and ultimately become a baby."
Previously: And baby makes four? KQED Forum guests discuss approval of three-parent IVF in UK, Oh baby! Infertile woman gives birth through Stanford-developed technique and Stanford researchers work to increase the odds of in vitro fertilization success
Image courtesy of Camarillo lab