March 17, 2009 - By Michelle Brandt
The question: Can a non-invasive test of a woman's eggs be used to predict in vitro fertilization success?
Background: IVF involves retrieving eggs from a woman's ovaries and fertilizing the eggs in a dish by incubating them with sperm or injecting sperm directly into them. The resulting embryos are then transferred back into the woman or placed in storage. (More than 400,000 embryos are in storage in the United States.) The egg quality is often the biggest determinant in the viability of the embryo.
The need: There is currently no good tool available to assess eggs. 'We would stand on our head and hop on our left leg if we could find a way to give us some information about the viability of an embryo,' said Barry Behr, PhD, HCLD, associate professor of obstetrics and gynecology and director of Stanford's IVF laboratory.
The technology: Metabolomic testing reveals trace molecules remaining after an array of cellular processes. Previous studies have shown that metabolomic profiling can be used to identify unique biomarkers left behind by embryos in culture, which 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.'
The study: The 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.
Publication: The study appeared online in the February issue of Reproductive Biomedicine. Behr is the senior author; Jennifer Dasig, an embryologist at Stanford, is one of the co-authors.
The findings: 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.
Barry Behr explains the value of metabolomics as a means for quantitatively evaluating the health of a woman's eggs and the implications for the future of IVF. Video length: 4 min
What's next: This is the first study to demonstrate that metabolomic profiling of the egg can generate important information about the resulting embryo. More studies are needed to confirm the results and to test it in greater numbers.
Implications: The test may someday be used to predict the success of IVF and to decide which eggs should be selected for fertilization or to be frozen. 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. This could also help avoid the practice of implanting numerous embryos into a woman, which sometimes leads to the birth of twins, triplets and higher-order multiples.
Added info: Behr is on the advisory board of Molecular Biometrics, which funded the study.
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