Implantation Failure: the importance of determining each woman’s unique personalized embryo transfer timing

As you may know, research in the field of Reproductive Medicine is one of the areas that has evolved the most in recent years, promoting and insisting more and more on the study of genetics to improve the selection of the best embryos and even the application of artificial intelligence. Unfortunately, in assisted reproduction treatments, there is always a part that does not depend on science and is related directly to biological factors and the patient herself. In this sense, we still find In Vitro Fertilization (IVF) cycles that end with an embryo implantation failure. Although a good quality embryo is the best starting point for implantation, endometrial receptivity is essential for implantation to be successful. But, before going on, we´d like to explain what implantation failure and endometrial receptivity mean:

• When we talk about implantation, we are referring to the adhesion of the embryo to the endometrium. Therefore, implantation failure occurs in In Vitro Fertilization treatment cycleswhen good quality embryos are transferred, but a pregnancy is not achieved.
• On the other hand, when we talk about endometrial receptivity, the first thing you should know is that the inside of the uterus is covered by a tissue called the endometrium. The endometrium is where the embryo implants and develops during pregnancy. The endometrium is receptive when it is ready for implantation to take place. This period of receptivity is what we call the window of implantation (WOI). Sometimes, we find that on the typical day of embryo transfer in an IVF cycle, the WOI is displaced.

Do we know which are the best days to carry out the embryo transfer?

Thanks to endometrial receptivity tests, we can determine whether or not the endometrium is receptive at a certain moment of the cycle by analyzing a sample of endometrial tissue. Since 2009, IGENOMIX holds the patent for the ERA Test (Endometrial Receptivity Analysis), the first diagnostic test that locates the personalized implantation window of each patient.  By doing so, this allows proper synchronization of the embryo transfer with the receptive period, increasing chances of success by optimizing the chances of pregnancy without losing good quality embryos. Through a computer predictor, designed by IGENOMIX, we classify the data obtained, indicating whether the endometrium is Receptive or Non-receptive. A receptive result indicates that the implantation window is located on the day the biopsy was performed, and the embryo will be able to implant in the uterus in that period of time. When the result indicates that the endometrium is non-receptive, it specifies that your endometrium is either pre-receptive or post-receptive. The results allow us to obtain an estimate of the implantation window for each patient, so that personalized embryo transfer can be performed. The ERA Test is recommended for all patients at the beginning of their assisted reproduction treatments, being especially beneficial for patients with previous implantation failures.