16 November 2002
ties in-vitro fertilization to genetic disorder
Finding called compelling, but more research needed
By Jonathan Bor
conceived by in-vitro fertilization may be at increased risk for
a rare genetic disorder that predisposes them to cancer, scientists
from the Johns Hopkins School of Medicine and Washington University
in St. Louis tracked children born with Beckwith-Wiedemann Syndrome
and found that an unusually large percentage were conceived by IVF.
the United States, fewer than 1 percent of all births were due to
in-vitro. But when doctors tracked 63 children born with the genetic
disorder - babies who were entered into a Beckwith-Wiedemann registry
after June 2001 - they discovered that more than 4 percent were
Andrew Feinberg, a Hopkins genetics professor, said the statistical
association does not mean that in-vitro can trigger the genetic
alterations responsible for the defect. But he said the finding
is compelling and should lead to further study.
is no central registry to track birth defects among babies conceived
through assisted reproductive technologies, even though about 40,000
babies in the United States alone were conceived last year with
only way you're really going to get a sure answer is to collect
information on a large enough number of IVF offspring," Feinberg
said. "This hasn't been done systematically."
added, "This analysis should not affect people's decisions
about whether to have IVF because our findings still need to be
study is due to be published next week in the online version of
the American Journal of Human Genetics.
Syndrome, occurring in about 1 in 15,000 births, causes children
to be born abnormally large, with large tongues and with poor closures
of the abdominal wall. This can produce hernias that must be surgically
the children are at high risk for developing cancers of the kidney,
liver and other tissues before puberty.
spring, a study published in a national journal found an elevated
rate of birth defects among in-vitro babies, but the study was considered
too small to be conclusive.
Philip I. McNamee, past president of the Society for Assisted Reproductive
Technology, says it is difficult to draw any conclusions about birth
defects among IVF children because there is no tracking system.
a professor at the University of Hawaii in Honolulu, said he hadn't
read the Beckwith-Wiedemann study but was intrigued. "You have
to be very careful drawing conclusions from this sort of data,"