Byline: JENNY HOPE
EMBRYOS created in fertility clinics have far more genetic defects than previously thought, even if they involve eggs donated by younger women, experts warned yesterday.
The discovery has led specialists to suggest that all women having IVF treatment should have their embryos checked for conditions such as Down's syndrome.
They say a new screening technique, currently offered only to older women in the UK, should be more widely available.
The results of the U.S. study contradicted the widely-held belief that the risk of genetic defects in eggs and embryos is higher for more mature women.
Researchers found that embryos from eggs donated by healthy young women had a 'startlingly high' level of genetic problems - up to 42 per cent.
This could explain why so many IVF patients fail to get pregnant.
Experts now believe that defective eggs are common among women of all ages, but those which are fertilised naturally are rejected early on by the body.
There is also concern that drugs used in fertility treatments, to stimulate egg production, may add to the damage.
Fertility specialist Dr Jeffrey Nelson, who headed the study in California, said it involved 289 embryos created from eggs donated by 22 women under 30.
The eggs and embryos all looked normal but the screening technique, called Preimplantation Genetic Diagnosis, found that 42 per cent had chromosomal abnormalities.
PGD takes a single cell from an eight-cell embryo and screens it for genetic abnormalities, including Down's. UK guidelines recommend that it is mostly used for infertile women over 35, where IVF treatment has failed, because the risks of genetic defects rises with age.
But Dr Nelson, managing partner of the Huntington Reproductive Center in Pasadena, said the UK policy was too inflexible. …