New IVF Test May Pinpoint Fertility Window

By MartaFF ( [CC BY-SA 4.0 (], via Wikimedia Commons

Currently, there are clinical trials underway in Madrid as medical researchers try to develop a test to pinpoint the window of a woman’s optimum fertile period. Hundreds of thousands of infertile couples could all benefit from this new test and it would tailor the timing of IVF treatments to a woman’s cycle.

The Test

The researchers behind the study believe that IVF most often is unsuccessful because the embryo is transferred during the wrong time, thereby missing a crucial fertility window.
The new test would assess the activity of the genes in the uterine lining to determine a woman’s best time for treatment. During pilot studies the comprehensive approach seemed to have a high rate of success.

Professor Juan Garcia-Velasco, of the IVF fertility clinic in Madrid states, “We think that about 15 percent of cases of implantation failure are simply due to bad timing.” Dr. Garcia-Velasco is currently leading a clinical trial for the test which involves 2,500 women from ten countries, including Great Britain.

Geeta Nargund, the medical director of Create Fertility in London is participating in the study and said, “The weakest link in IVF is implantation failure. I believe this is a breakthrough.”

In Britain, there are more than 60,000 cycles of IVF each year, but less than a quarter of these treatments leads to a successful live birth. Clinics currently view the visual appearance of the uterine lining via an ultrasound, which is generally an indication of a woman’s health.

Nargund went on further to state,” What we have never known is the right window for implantation. If you miss that window, no matter how beautiful the embryo, it’s not going to implant.”

Most women have around a two to four day window of opportunity, when the uterine lining emits a crucial chemical signal that allows an embryo to successfully attach itself. For some women, the fertile window may shift to earlier or later in her cycle or is unusually short.

With the new test, an endometrial biopsy is performed and the gene activity is tested. As the cells go into the receptive phase, a series of genetic switches go off like clockwork. Using this test could make a significant difference in a couple’s expectations and if this was a problem in the past, it can now be corrected.


In the new study, the test was provided to about 85 women who had each experienced on average about five rounds of IVF, but failed during the implantation stage. In these subjects, the window of successful implantation had likely shifted or was abnormally shortened. In some instances, cases entirely missed the day when the embryo is transferred into the uterus.

When gene analysis was utilized, 33 percent of those women treated experienced successful implantation. In the international trial, the test will be provided for women who have had two or more previously failed IVF implantations.

Ultimately, the IVF team is trying to at least develop a less invasive version of this test, based on sampling uterine fluid. The current assessment is performed at least a month before an embryo transfer, because the action of disturbing the uterine lining interferes with implantation success.


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