The endometrium plays a very important role in achieving a healthy pregnancy through assisted reproductive technologies like IVF. The readiness of the endometrium for the implantation of the embryo is called endometrial receptivity.
Endometrial receptivity test is a medical process in which a small sample of a woman’s endometrial tissue is assessed to check if her endometrial lining is developed enough to accept an embryo successfully. Getting pregnant is a complex process that requires the embryo and a woman’s endometrium (uterine lining) to meet at just the right place at the right time. Pregnancy will not occur if the embryo and endometrium do not interact in the right way and the implantation doesn’t happen. Therefore, for pregnancy to occur, the endometrium should be of a certain thickness and must express the correct genes to tell the embryo that it is ready for implantation. Furthermore, the embryo must have reached the blastocyst stage to successfully implant.
In simple words, endometrial receptivity test is a genetic test that helps women who are pursuing In Vitro Fertilisation (IVF) determine whether their endometrium is receiving an embryo at the right time to maximise their chances of a successful pregnancy.
What is the window of receptivity or window of implantation?
Endometrial receptivity is that stage in a women’s menstrual cycle when the uterus is prepared to receive an embryo for implantation. This stage occurs in a time frame called the ‘window of implantation or ‘window of receptivity’ that usually lasts for 3 to 6 days after ovulation in most women. While most women (80 per cent) have this window at the expected time, the rest tend to have a displaced window of implantation that occurs later or earlier than expected. In some inflammatory or anatomic conditions, this time frame is changed to prevent normal implantation, causing infertility and multiple IVF failures. Approximately 238 genes determine the window of implantation and govern endometrial receptivity. This window of implantation is universal for all women and can vary based on the woman’s progesterone level and other factors.
Who should opt for the Endometrial Receptivity Array Test (ERA Test)?
Endometrial Receptivity Array test (ERA Test), also known as the Endometrial Receptivity Analysis, is done before the frozen embryo is transferred in the next IVF cycle to determine a patient’s endometrial receptivity. Are you wondering whether you should get the ERA Test done? It is advisable to opt for an ERA test if you have had two or more unsuccessful embryo transfers, have a thin endometrial lining, or have had unsuccessful implantation of good quality embryos.
How is Endometrial Receptivity Array Test (ERA Test) performed?
A tiny catheter is inserted through the cervix to draw out a sample of the endometrial lining during the implantation window for the ERA test. Then, the sample is analyzed using Next Generation Sequencing technology. An advanced computer algorithm is used to determine whether the sample is receptive or non-receptive as the genetic material of endometrial cells have a distinguished expression when it’s receptive. If the tissue is found to be non-receptive, the process is done again until the perfect implantation window is found.
Is Endometrial Receptivity important if you are undergoing IVF?
This ‘window of receptivity’ is present in natural conception and IVF. In IVF, this information helps the doctors to determine when they can schedule an embryo transfer for successful implantation. In IVF treatment, it is essential to find the window of receptivity before transferring the embryo to the uterus to avoid implantation failure. A couple could face a lot of emotional stress and anxiety while undergoing IVF treatment. Modern technologies like the ERA offers assurance and hope to such people by reducing the chances of implantation failure.