An IVF test which checks whether embryos carry the correct number of chromosomes could improve the chances of a successful pregnancy, a clinical trial suggests.

The test – developed by the biotech company Blue Gnome – is used five days after an egg has been fertilised and helps doctors select which embryo should be implanted during fertility treatment.

In a clinical trial published in the Journal of Molecular Cytogenetics, using the test resulted in a 65 percent increase in pregnancy at 20 weeks compared to the control group. In total 103 IVF cycles were included in the trial and all the women were under 35.

Dr Simon Fishel, managing director of CARE Fertility, who has helped develop several IVF screening techniques during his career, said the paper represented 'a breakthrough clinical study, showing for the first time how this technology, which CARE helped pioneer, can greatly improve IVF success rates for younger patients'.

Evidence suggests that abnormal chromosome number, called aneuploidy, in embryos significantly reduces the chances of IVF success. Aneuploidy is relatively common and in most cases means the embryo will not develop.

In the new test, called 24sure, cells are extracted from five-day-old embryos. The DNA from these cells is analysed; according to a promotional website, 'over 3000 measurements are made, covering all available chromosomes'. The results are available in 12 hours which means that embryos do not have to be cryopreserved while the test is running.

Currently, for women under 35 only around a third of IVF cycles lead to a live birth, with that figure decreasing as women age. Any technique that would increase pregnancy rates is therefore highly sought after. Such a development would also reduce the drive to implant more than one embryo during IVF, which can result in risky multiple pregnancies.

Although this is the first clinical trial of 24sure, the test is already used in fertility clinics. Blue Gnome's website says that the technique is 'widely available in the UK through a number of private IVF centres'.

Blue Gnome CEO, Nick Haan, says that while further studies are still needed, his company's product has the 'potential to become the default standard of care for all IVF cycles worldwide'.

Professor Dagan Wells, from the Nuffield Department of Obstetrics and Gynaecology at the University of Oxford, told the BBC that 'more research is needed to nail down who will benefit, but my gut feeling is that it is valuable'.

Reproduced from BioNews with permission, a web- and email-based source of news, information and comment on assisted reproduction and human genetics, published by Progress Educational Trust.