The connection? It could be the result of some kind of underlying—and still unknown—health issue among children of mothers who underwent fertility treatments such as IVF, say researchers. But another plausible explanation? After putting so much time and effort into getting pregnant, IVF moms may be more cautious about their child's health—and, thus, much more likely to report symptoms at the first sign of wheezing.
Here's what the study found. Using data from a nationwide healthy survey of more than 18,000 children born in the UK between 2000 and 2002, researchers noticed that at age 5, children born to parents considered "sub-fertile"—meaning couples who took longer than a year to conceive or who conceived via some form of assisted reproduction technology (ART)—were consistently more likely to have developed asthma, wheezing, and to be taking anti-asthmatic medication. For example, while 15 percent of all children had asthma by age 5, 24 percent of children conceived through IVF had been diagnosed with the disease by the same age.
Researchers scratched their heads at first after unearthing the unusual statistics because they just couldn't tell what was behind the numbers. "Although we found an association... further research is needed to establish what might be causing the association and the underlying mechanism involved," says study author Dr. Claire Carson, a researcher at the National Perinatal Epidemiology Unit at the University of Oxford, in a press release.
However, Carson does venture a guess that any one of several reasons could explain the link between fertility treatments and asthma, such as the severity of the infertility, the type of treatment, and even perhaps that over-protective IVF parents are more likely to report asthma symptoms.
Researchers are betting that a medical explanation is behind all this, and doubt that overly worried parents are completely to blame. In their minds, the only way to settle the issue is through, well, more research!
But moms who have gone through the roller coaster of infertility and IVF treatments before getting pregnant?
"Oh, I think there is totally something to this," says Amanda Crosby, from Manalapan, New Jersey, who used IVF to conceive her second child after being diagnosed with secondary infertility.
"My son is very young, so the memory of what we went through to have him is still fresh. If I even notice the slightest runny nose, I am all over it. You better believe if I thought he had asthma, we would be at the doctor's that same day."