IVF May Damage Baby's Genes, Researchers FindJan 17, 2003 | The Sydney Morning Herald
IVF babies are about three times as likely as others to be born with a rare genetic syndrome, researchers have found the strongest evidence yet that assisted reproduction techniques may damage a baby's DNA.
A British study of 149 children with Beckwith-Wiedemann syndrome which usually affects about one in 15,000 births and causes excessive growth and increased cancer risk found six had been conceived through IVF or related techniques.
Only one or two would be expected to be IVF children, based on the rate of IVF births in the community as a whole, said Eamon Maher, from the University of Birmingham.
Professor Maher suggested the culture fluid in which IVF embryos are grown may be responsible. If true, he said, this would be of increasing concern because many centres now grow embryos in the laboratory for up to six days instead of the more traditional two or three.
"With the trend towards extending in-vitro culture times it will be increasingly important to address these questions in large scale studies of children," he wrote yesterday in the Journal of Medical Genetics.
The medical director of Sydney IVF, Robert Jansen, said doctors already knew from animal studies that IVF could damage genetic material. "Luckily, human embryos appear to be a lot less vulnerable," Professor Jansen said.
It was likely other medical syndromes about 50 in total caused by similar "genetic imprinting" errors to Beckwith-Wiedemann could occur at higher rates in IVF children, he said. Because such conditions were already very rare, huge studies would be required to conclusively detect any increase.
Only a small minority of genes are imprinted, or expressed differently according to which parent passes them on.
"In the overall scheme of things, IVF is safe. It would be amazing if such a difference in the first few days of an embryo didn't make a difference. People have IVF for definite needs and those needs are not going to go away," Professor Jansen said.
Extended culture times might, in fact, result in healthier IVF babies, he said, because doctors could select healthier embryos.
The professor of reproductive medicine at the University of Sydney, Ian Fraser, said the new results strongly suggested DNA damage could occur after IVF. "It's really important that it's followed up," he said.
But IVF specialists had been pleasantly surprised at the low rate of birth defects. Initially they had been "very concerned about how we were suppressing the natural selection aspect of reproduction you are bypassing a number of filtering processes" that normally prevented some people with subtle health problems from having babies.