Researchers find higher levels of gene proteins linked to successful development.
New Zealand researchers hope to greatly improve the efficiency of making babies in the laboratory by developing an accurate egg test.
Expensive tests exist but the experimental one would be much cheaper and could be used to screen eggs at the time they are removed from women during in-vitro fertilisation (IVF) treatment.
Victoria University post-graduate student Jozsef Ekart, who will present the research to the Fertility Society of Australia meeting in Auckland tomorrow, won a prize for a summary he gave to an American fertility conference last week.
"We want to find a non-invasive method to predict which egg will form a pregnancy," he said.
Mr Ekart and others from the university and the Fertility Associates clinic in Wellington have found that higher levels of proteins expressed by three genes from the "cumulus" cells surrounding an unfertilised egg are associated with healthy development of the egg following fertilisation. They hope to find a fourth predictive gene protein.
"We are getting about 70 per cent predictive value," said Professor John Hutton, of Fertility Associates.
"We need to get up to 90 per cent if possible. I think we can get up to 90 per cent."
He said the implication of the test was that you shouldn't transfer into a woman's uterus any embryos from eggs that didn't measure up.
The test had the potential to increase the efficiency of IV Ftreatment.
An Auckland IVF mum and veteran of multiple miscarriages - who asked not to be identified - welcomed the possible advantages of the experimental test.
She has two daughters aged 10 months and 4 years conceived from two of the three IVF cycles she went through.
They woman, aged 39, lost seven pregnancies, including several that were conceived naturally between the second and third IVF cycles and following laparoscopic treatment for endometriosis.
She said the experimental test "sounds fantastic - just knowing that you've got that little bit more information".
Repeated miscarriages were "pretty taxing" she said.
What is the aim of the research?
To find a test that will predict with high accuracy whether a human egg has the capacity, once fertilised, to develop properly and lead to a live birth.
What did the researchers test?
An unfertilised egg is surrounded and nourished by cumulus cells. The researchers tested the cumulus cells from eggs taken from women during in-vitro fertilisation (IVF) treatment. They looked for certain proteins from particular genes and matched the results with the quality of each egg, embryo and pregnancy outcome.
What did they find?
Of eight genes investigated, three were found to have higher average protein levels when they came from cumulus cells whose eggs went on after fertilisation to develop properly into "blastocysts" for freezing or transfer into the woman's uterus on day 5 or 6 - compared to the eggs which failed to develop. Higher average levels of one of the three gene-expression proteins was associated with eggs that resulted in a live birth.