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Personalised test could fine tune IVF treatment

New test assesses activity of genes in the womb lining to pinpoint optimum time for intervention

Mark Gould

Monday, 09 March 2015

A personalised test tuned to the woman's reproductive cycle could benefit many thousands of infertile couples receiving IVF treatment.

Scientists in Spain who are pioneering the test believe that IVF frequently fails because the embryo is transferred into the womb at the wrong time. Less than 24% of the IVF implantations done at present in the UK translate into live births. The new test assesses the activity of genes of the womb lining to pinpoint a woman’s optimum time for treatment and in pilot studies the personalised approach appeared to significantly boost success rates.

Prof Juan Garcia-Velasco, from the IVI fertility clinic in Madrid told The Guardian: “We think that about 15% of cases of implantation failure are simply due to bad timing.” Prof Garcia-Velasco is now leading a clinical trial of the test, involving 2,500 patients in more than ten countries, including Britain.

For most women there is a two to four day stretch when the lining, or endometrium, sends out crucial chemical signals that allow the embryo to attach. For some women the fertile window is shifted earlier or later in the cycle or is unusually brief, however.

In the new test, a biopsy of the endometrium is taken and the gene activity is analysed. As the cells enter the receptive phase a series of genes switch on and off in a reliable sequence that scientists can read like a clock.

In a pilot study, the test was given to 85 women who had each experienced on average five rounds of IVF that had failed at the implantation stage. In these women, the fertile window was more likely to be shifted early or late, in some cases completely missing the day when the embryo is transferred in standard IVF protocols, the study found.

When the gene analysis was used as a guide, 33% of those treated had a successful implantation – considerably higher than would typically be seen for such a group, Garcia-Velasco said. “This is probably the most difficult population in IVF. Some of them benefit just by changing the day,” he said.

In the international trial the test will be offered to women who have had two or more previous instances of implantation failure. Ultimately, the IVI team is aiming to develop a less invasive version of the test, based on sampling endometrial fluid, that could be used at the time of treatment. The current assessment is done at least one month before the embryo transfer because the act of disturbing the womb lining itself interferes with implantation.

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