Infertile couples are to be offered a controversial embryo quality test that could double their chances of starting a family.

At least 90 women are to be recruited by a clinic in London to take part in the study, which promises to settle a heated medical dispute about the test’s capacity to help IVF patients.

Preliminary research in the US has suggested that the procedure, which aims to identify embryos with the best chance of developing into healthy babies, can deliver IVF success rates as high as 80 per cent — more than double the average in Britain.

These results, however, are highly contentious because the patients were not compared with a control group having normal IVF. Many doctors doubt that the test works as claimed, and some say that to offer it is unethical. The new study should resolve the issue because it will be the first to evaluate the technique in a randomised controlled trial — the gold standard for medical research.

Details of the trial were revealed as the European Society of Human Reproduction and Embryology announced plans for its own study of a different screening technique intended to boost IVF success rates.

Professor Joep Geraedts, chairman of the society, told its conference in Amsterdam yesterday that it would sponsor a pilot investigation of a tool to assess the quality of patients’ eggs, with the intention of starting an international randomised trial.

Dagan Wells, of Reprogenetics UK laboratory in Oxford, who is leading the British study with Kamal Ahuja, of the London Women’s Clinic, said that research was critical if quality checks were to become widely available: “We need to find out whether this technology can detect viable embryos and deliver the results we think it should.”

The procedure will screen IVF embryos for chromosomal abnormalities called aneuploidies, which are a common cause of infertility and miscarriage, before they are transferred to patients’ wombs.

More than half of all embryos are aneuploid, which means that they have too many chromosomes or too few. Most of these fail to implant in the womb or miscarry, while the few that survive have chromosomal disorders such as Down’s syndrome.

While a pre-implantation genetic test for aneuploidy is available, it is controversial because there is little evidence that it helps women to conceive. Some studies have even suggested that it is harmful, and the British Fertility Society recommends that it should be offered only in clinical trials.

The trial in London will evaluate a newer aneuploidy screening technique called comparative genomic hybridisation (CGH), which is believed to be more reliable because it can examine all 23 pairs of chromosomes, compared with only 10 pairs for older methods. The CGH test is also performed on embryos at the blastocyst stage of 100 to 150 cells, which allows more cells to be removed for genetic analysis, giving increased accuracy.

The test requires blastocysts to be frozen while tests are performed. This became plausible because of a new freezing technique called vitrification, which makes it easier to thaw the embryos for transfer to the womb without damage.

The trial will begin in the autumn. Dr Wells said: “The area of controversy is not so much the theory, but the lack of evidence from robust trials that this technology can deliver improved IVF success. That’s what we hope to provide with this trial.”

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