Introduction:
The endometrial receptivity network is a test claiming to discover the optimal time for an embryo transfer into a woman's uterus for implantation, and this time interval is known as the window of implantation. The primary procedure of this test is taking a biopsy of the endometrial lining and testing the tissue to see which genes are expressed. When combined with computer prediction equipment, these results will indicate when the endometrium may be most receptive to implantation. The endometrium will be classified as receptive, pre-receptive, or post-receptive.
During subsequent treatment cycles, the patient will benefit from so-called “personalized embryo transfers,” which take place at the optimal time of the specific implantation window. Theoretically, this should increase the chances of the embryo successfully implanting, and the patient will have a baby. However, the question is whether patients will have the same implantation time for each of their treatment cycles.
A clinical trial was conducted to study the effectiveness of ERA in increasing patient's chances of having children. The results of the study were promising, but they do not prove that ERAs make a real difference in a patient's chances of having children, and the doctors cannot be certain about their reliability.
What Is the ERA Test?
Endometrial receptivity array is a hereditary test used for the assessment of when the uterine lining is most receptive to an embryo. This test was developed in an effort to improve embryo implantation in women who have had multiple unsuccessful embryo transfers. This technique evaluates the uterine lining by analyzing 236 genes related to its receptivity. These genes have been identified by scientific research as important for implantation. This analysis helps determine the timing of implantation so that personalized embryo transfer (pET) can be performed. Although adequate basic research has been conducted, it is still unclear whether this test improves fertility treatment outcomes.
HFEA, the Human Fertilization & Embryology Authority, regularly studies therapeutic supplements and assigns levels to them using a traffic light system. The list of add-ons is classified by traffic light, including three colors that indicate whether the evidence, in the form of high-quality trials, is effective in improving the chances of giving birth to one's child during the reproductive period or not. HFEA evaluates the Endometrial Receptivity Chart as an RED add-on.
When Is It Recommended, and Why?
ERA testing is not routinely recommended because it has not been proven to make a difference in the outcome of fertility treatment in most people. However, in women with repeated implantation failure, an ERA test may be performed to determine the best time for embryo transfer.
Because the evidence for this test is inconclusive, it is not considered as a mandatory test. It is gauged that 24 percent of patients have recurrent embryo transfer failures due to a lack of coordination during the process, leading to IVF (in vitro fertilization) failure. ERA was developed as a way to determine this time period more accurately to improve the chances of pregnancy for those undergoing IVF.
Typically, the test is recommended after multiple failed implantations or if there is another reason for the patient to be concerned about a thin uterine lining. Evaluating the mucosa with the ERA test allows fertility doctors to determine the best date for the embryo transfer procedure.
What Are the Advantages of ERA?
This test indicates the timing of implantation, aiming to optimize embryo transfer time. This approach is also known as “personalized embryo transfer” (pET). This test is most likely to benefit women whose implantation window is displaced. However, implementation is complex and depends on many factors. Therefore, there is no guarantee of success after ERA and personalized embryo transfer. It is important to note that there are no good studies demonstrating that testing improves the chances of having a baby with treatment.
What Are the Disadvantages of ERA?
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Testing will incur additional costs, and ERA testing is not included in the cost of the treatment cycle.
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The patient must take hormone medications that may cause hormonal side effects. In addition to medication, a biopsy of the uterine lining is also required, which is somewhat invasive and may cause discomfort. Having this test may delay the treatment by at least one menstrual cycle.
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The results may be inconclusive, and in this case, the patient may need to undergo further testing.
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The procedure itself can cause discomfort and irregular bleeding, with a tiny threat of pelvic infection.
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There is no convincing evidence that embryo transfer based on ERA test results improves treatment outcomes. The cost of an ERA is an additional expense compared to the cost of fertility medications, and most medical visits can be significant for the patient.
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The additional cost and time required are among the limiting factors as to why this test is not used in more IVF cycles in the first place. However, some patients should consider having more tests done, such as ERA upfront. This additional expense can make the difference between one successfully timed IVF cycle and many failed cycles.
How Does ERA Work?
This test involves an endometrial biopsy, in which a small, painless tissue sample is collected and genetically analyzed to determine the optimal timing for hormone administration and implantation during an IVF cycle now or later. Typically, most procedures involve transferring the embryo on the fifth day of embryo growth. However, for about 30 percent of women, this estimate is incorrect; some may need embryo transfer earlier or later, and this is when ERA testing may be performed. The test result is “responsive” or “unresponsive.” If the patient does not respond, a second ERA test is often needed to determine the WOI (window of implantation).
However, if the patient is receptive, this may allow embryos to be transferred on the same day for greater success. If the embryo transfer takes place next month, it will take place on the same date but one month later. This gives fertility doctors a chance to prepare the eggs or embryos so they are ready to be implanted in the uterus the following month. Although ERA testing involves additional costs for about 30 percent of patients, knowing the optimal time for embryo transfer can be helpful in avoiding additional IVF procedures. One must discuss with the doctor to determine if ERA testing is required or not.
Conclusion
It is clear that ERA is a new technology that helps evaluate and provide a large amount of information about the patient's endometrial receptivity. From the provider's perspective, analysis only requires performing an endometrial biopsy. Although ERA may not improve outcomes in every patient seeking fertility treatment, it has clear benefits for specific populations. In these contexts, ERA can bring many benefits. When considering the ERA, the situations in which it might be used, and its effectiveness in a number of different populations, it becomes clear that the conversation should focus less on whether the ERA is a tool effective or not but rather on when it can be used effectively.
