This week Britain's leading fertility expert, Lord Robert Winston, spoke out at Cheltenham Science Festival to express his disappointment that IVF success rates have plateaued over recent decades, a trend which he believes is partly due to complacency. New technologies for selecting both viable eggs and healthy embryos are needed in order to improve on success rates, he says.
IVF involves artificially stimulating the ovaries with hormones in order to encourage them to release a large number of eggs simultaneously, but Lord Winston says this creates an unfavourable hormonal environment for harvesting viable eggs. Researchers need to leave less to chance, he says, by developing novel techniques for identifying the healthiest eggs - those most likely to lead to viable embryos. 'I can see in five or ten years time at most, new therapies to produce eggs which are much more likely to be viable and the embryo quality depends on the quality of the egg,' he said, quoted in the Daily Telegraph.
Embryo selection is currently based on observations of morphology (shape and appearance) to predict their potential viability, an unreliable process which means clinicians often have to transfer more than one embryo to achieve pregnancy, risking multiple births. Clinicians need to develop a definitive way to pick a single, viable embryo, says Lord Winston.
A group of Australian scientists are currently working to develop a new genetic analysis technique for pinpointing those embryos most likely to develop in the womb. The group is working on eventually identifying a subset of five to ten genes that could be put into a very rapid same day test for use in IVF clinics. Although promising, Lord Winston believes that such techniques will quickly be superseded by less invasive and expensive ones.