The study, published in the Public Library of Science journal, identifies factors that will indicate with 70 percent accuracy the chances of pregnancy after a single round of in vitro fertilization, or IVF.
In vitro fertilization is a process by which eggs and sperm are clinically combined to create viable embryos that are then transferred into the uterus. Nationally, anywhere from 18 to 45 percent of IVF treatments, on women using their own eggs, result in pregnancy, according to the Society for Assisted Reproductive Technology.
Stanford researchers isolated four factors out of 30 to better predict pregnancy outcomes: the total number of embryos developed during fertilization; both the number of fully developed and undeveloped embryos; and a hormone test.
But the scientists' method only tells parents who've already undergone one round of IVF if the treatment likely worked, said Dr. Mylene Yao, the lead researcher on the study and Stanford assistant professor of obstetrics and gynecology. What the method doesn't predict is the parents' chances of a pregnancy should they try IVF again, assuming the first attempt failed.
The Stanford researchers analyzed 665 IVF trials conducted at the university in 2005.
The researchers are now analyzing a larger set of birth data from another study.
"Ultimately we want to be able to give patients more personalized and evidence-based information to help them decide whether they want to have IVF treatment if their first one (treatment) does not result in a baby," Yao said.
For the most part, scientists already know to look at both undeveloped and developed embryos, said Dr. Susan Willman, an endocrinologist with the Reproductive Science Center of the San Francisco Bay Area. What the study does is calculate an actual probability, the first time she had read of one.
The trend in endocrinology research is to develop tests that predict the likelihood of pregnancy before fertility treatments begin, Willman said. Research is also focused on determining which embryos are healthiest to transfer.
Yao emphasized the study is one more way scientists pinpoint when IVF is most likely to work.
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