IVF success may increase by 50 percent if only scientists are able to pick the squishiest embryo in the bunch, a new study found.

The death of embryos before implantation is a puzzle that experts are yet to solve. Now, a new study from Stanford University discovered that the key to embryonic survival and viability is to have a texture that is neither too hard nor too soft.

Such discovery may significantly amp up the success of single-egg IVF and consequently provide better outcomes both for the mother and the child.

Conventional Embryo Selection

At present, scientists select embryos for IVF based on its form and the rate at which it divides. First, they fertilize an egg with a sperm. After five to six days, when the embryo turns into what experts call blastocyst, the scientists evaluate and determine the best-looking ones for transfer.

While such procedure for genetic testing boosts successful selection, it also increases the risk of damage and stress to the embryo. This is true even if scientists only pluck a few cells, which will also form the placenta later on.

"A lot of twins are born because we don't know which embryos are viable or not, so we transfer several at one time," says study lead-author Livia Yanez. This may result in increased deaths among babies and complications in both mothers and babies.

With this, Yanez and colleagues wanted to create a mechanical test that could determine the viability of an embryo so doctors need to implant just a single good one.

Squishiest Wins

The authors heard about how some eggs are squishier than others. They took this note seriously and decided to focus their study on this concept.

They applied little pressure on mice egg using a small pipette, one hour after fertilization. They then documented the rate of the egg's deformation. When the egg reached the blastocyst phase, the researchers took another look and found that those that exhibit good "push back" as eggs became the healthier-looking blastocysts.

The authors then translated this into a computer model. This model is now recognized to predict which fertilized eggs will form into good blastocysts with 90 percent accuracy.

When the scientists transferred the embryos to mother mice, those classified as viable through its squishiness were found to yield 50 percent more successful live births than conventional screening methods.

Co-author David Camarillo says it is surprising to learn that such simple mechanical test can help determine which embryos will grow into babies.

Testing On Humans

The scientists also tested their discovery in human fertilized eggs and found that the squishiness test can also predict which eggs will grow into healthy blastocysts with a 90 percent accuracy rate.

Currently, the team is looking at testing this method in patients.

The study was published in the journal Nature Communications on Feb. 24.