In the process known as in vitro fertilization (IVF), the quality of the egg is often the single greatest factor in the viability of the embryo, yet fertility experts lack a good method for assessing the eggs. Now, Barry Behr, director of Stanford's IVF laboratory, has published findings on a way to "profile" the eggs to determine which are more likely to result in pregnancies.
Known as metabolomic testing, Behr explained that the test could be used to foretell the embryos with the highest reproductive potential in IVF. "Think of it as a sort of smog test for the embryo," said Behr. "It tells you how clean the engine is burning, and whether there are any problems."
Behr's study involved extracting eggs from 43 women, incubating them in culture for three hours and then examining their metabolomic results before fertilization. The researchers then documented what happened to each egg: Whether it was fertilized, the quality of the resulting embryo on days three and five, and whether it led to a successful pregnancy.
The researchers established a correlation between the number of particular trace elements left behind by the eggs and both embryo viability and pregnancy rates. "This shows we can predict embryo development and viability from the egg," said Behr.
This is the first study to demonstrate that metabolomic profiling of the egg can generate important information about the resulting embryo. If future studies confirm these results, the test could someday be used to predict the success of IVF and help determine which eggs should be selected for fertilization or to be frozen, Behr said. Using only the best-quality eggs would lead to the creation of fewer embryos and eliminate the need to keep large quantities of embryos in storage.
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Source: Stanford University Medical Center