Researchers at McGill and Yale universities say they have found a safe way for women to use in-vitro fertilization which reduces the risk they'll bring home enough babies to fill a nursery.
McGill chemistry Prof. David Burns led the team which designed the test, a non-invasive procedure which will allow clinicians to choose only the healthiest, most viable embryos to implant in the womb.
"I don't know that I'd call it a eureka moment, but I'm always happy when a hypothesis I think might work turns out," said Burns, who has specialized in biospectroscopy - molecular analysis of living tissue and fluids - for 20 years.
Over the last 25 years, the number of multiple births in North America has skyrocketed, largely as a result of so-called "fertility" twins, triplets and quads born to mothers who conceived with help of assisted reproductive technology.
In the United States, for instance, the number of twin births soared by 42 per cent between 1980 and 1997, while reports of triplets and more was five times higher. According to statistics compiled by Multiple Births Canada, 60 per cent of triplets, 90 per cent of quads and 99 per cent of quintuplets in Canada are the result of infertility treatments.
Fertility specialists often implant three or more embryos in their patients, knowing that only one-third of procedures normally result in pregnancy. Yet of those that do take, half result in multiple births.
And while most couples are thrilled with their long-awaited bundles of joy, more babies often means more complications, such as low birth weight, premature delivery, and greater risk of infant mortality or complications.
"IVF can be an emotional roller-coaster," said Dr. Hing-Sang Hum, assistant professor of obstetrics and gynecology at McGill.
"With this breakthrough, it means we may soon be able to implant just one embryo, one that is showing strong signs of viability, while preserving other good embryo candidates for later if needed."
The technology awaits approval by the U.S. Food and Drug Administration, but Burns said he hopes to see ViaTestTM-E in production before the end of the year, replacing current screening methods, which hinge on a visual inspection of embryos through a microscope.
"The successes of in-vitro fertilization often result from simultaneous transfer of multiple embryos with the hope that at least one will lead to a pregnancy."
Building on earlier findings by McGill colleagues Kristine Koski and Hyman Schipper, the team established a metabolic profile of what constitutes a healthy embryo. Burns developed software to examine the molecular composition of fertilization fluid. This allows scientists to identify healthy eggs without interfering with them.