IVF success rate 'could be doubled'
Mapping the genetic code of fertilised eggs could double the success rate of IVF, researchers claim.
The new screening method to detect healthy embryos could raise the success of IVF to 60% or more, according to a Peking University and Harvard University team.
Trials of the procedure in China offer hope to older women, they say.
The research, in the journal Cell, should be viewed with caution, said a UK fertility expert.
IVF involves joining a woman's egg and a man's sperm in a laboratory dish, then transferring embryos into the mother's womb.
In order to maximise the success of IVF, various screening procedures can be used by fertility clinics to select the most healthy ones for implantation.
These approaches often involve removing cells from the growing embryo, and may not pick up all genetic problems.
The new method, studied in 70 fertilised eggs from volunteer egg donors, was based on removing left-over fragments of cells, known as polar bodies, from the early developing embryo and analysing their full genetic code.
Lead researcher, Jie Qiao of Third Hospital, Peking University, said: "Theoretically, if this works perfectly, we will be able to double the success rate of test tube baby technology from 30% to 60% or even more."
Proof of principle
The technique allows DNA contributed by the mother to the growing embryo to be screened for genetic abnormalities that might lead to IVF failure, miscarriage, or genetic problems in the child, said co-researcher, Xiaoliang Sunney Xie, of Harvard University.
It would be of most use to women with repeated failures of IVF and could improve the success rate of fertility treatment, particularly in older women, he said.
"In this paper we have a proof of principle - the clinical trial has already started," he told BBC News. "It does offer hope to women with repeated failure of IVF."
However, a UK expert urged caution. Commenting on the research, Dr Yacoub Khalaf, consultant in reproductive medicine and surgery at the Assisted Conception Unit at Guy's Hospital, London, told BBC News: "The area of screening is appealing in theory but in practice has not delivered.
"If screening eggs or screening embryos is not robust and reliable it could cost women their eggs or their embryos, both of which are precious and finite."
Infertility affects up to 15% of couples around the world, with many turning to IVF to have a child.