Endometrial receptivity testing is a way to narrow down a woman’s window of implantation prior to an embryo transfer, but is this test appropriate for every woman who has undergone an IVF cycle? When the test was first developed, its primary indication was for women with recurrent implantation failure. As we learn more about the test though, we’re finding that there may be a benefit to using it for other indications.
The endometrial receptivity test involves a woman undergoing a mock cycle, where she takes all of the same medications that she would for an embryo transfer cycle. In the mock cycle though, the woman does not actually undergo an embryo transfer. Instead, on the day that an embryo would have normally been transferred, the woman undergoes a biopsy of her uterine lining. The biopsied tissue is then sent to a specialized laboratory, where over 200 different genes are analyzed in the sample. All of these genes are thought to play a role in implantation. Based on the analysis, it is determined whether or not the tissue is “receptive” to implantation. If it is not “receptive”, in most cases, adjustments can be made to correct this.
It was previously thought that every woman had the same window of implantation. For years, most IVF specialists were transferring embryos on a specific day of a woman’s cycle, assuming this was the correct day of implantation for all women. Based on data from the endometrial receptivity test though, we learned that approximately 25% of women have a displaced window of implantation.
Since the majority of women do not have a displaced window of implantation, it is reasonable to reserve the endometrial receptivity test for women who have recurrent implantation failure, meaning that they have not conceived after multiple cycles of transferring good quality embryos. In my opinion though, the test may also be beneficial for women who do not have many good quality embryos. For these women, narrowing down the window of implantation to begin with may give them the best chance of conceiving of pregnancy with the few embryos they have.
There are still multiple ongoing studies about endometrial receptivity testing, so we may even learn in the future that the test is beneficial for all women undergoing IVF. For now though, if you’ve had recurrent implantation failure or if you have few embryos, you may want to speak with your fertility specialist to see if you may benefit from this test. There is no harm in asking.