IVF Babies May Have Slightly Higher Cancer Risk
Researchers Say Infertility, Not in Vitro Fertilization, May Be Behind Elevated Cancer Risk
IVF Babies and Cancer Risk: Message for Parents
What's the message for those undergoing or considering IVF? "I think that any couple who considers IVF should know that there is a moderately increased risk for complications for their children-to-be," Kallen says.
It's also important, he says, to maintain perspective. "Most IVF pregnancies end with the birth of a living, normal child, and the risk should not be exaggerated."
He suspects the findings from the Swedish study would hold true for the U.S. population but can't say that with certainty.
IVF Experts Weigh In
The new study findings are looked on as important by two IVF experts who reviewed the study for WebMD.
Although previous research has suggested IVF is associated with an increased cancer risk for the babies, the new study is believed to be the first to show a scientifically strong link, says William Gibbons, president of the American Society for Reproductive Medicine and professor and director of the division of reproductive medicine at the Baylor College of Medicine in Houston.
''More [studies] will help validate," he says. Based on what researchers know now, he says, "we think the risk is small."
He agrees with Kallen that the increased cancer risk may be associated with the infertility, not the IVF itself. "Avoiding IVF may not make the risk go away," he tells WebMD.
"The bottom line is this: If there is a risk, it is a small risk," James Goldfarb, MD, director of infertility and IVF at the Cleveland Clinic and president of the Society for Assisted Reproductive Technologies.
Regarding the six IVF-conceived children with a diagnosis of Langerhans histiocytosis, he says the condition is ''most definitely not a cancer." Still, the link held after excluding these six cases.
In IVF, he says, ''the critical factor is the number of embryos transferred. If you look at IVF over the years, the vast majority of health issues is due to multiple pregnancies."
Under guidelines from the fertility specialty organizations, Goldfarb says, doctors generally are advised to transfer no more than two embryos in women under age 35. In older women, more could be transferred, taking into account the woman's likelihood of getting pregnant and other factors, he says.