Endometrial Receptivity Analysis (ERA)
You may have seen Dr. Tur-Kaspa on Good Morning America or in National Geographic’s 2019 special edition on personalized medicine. That is because at IHR were one of the first to use the endometrial receptivity analysis test routinely in the United States. The ERA test evaluates the status of the woman’s endometrial receptivity to prevent implantation failure
We at IHR always tried to give any woman the best chance to conceive from the first trial. We therefore emphasize obtaining good quality embryos, and especially when possible, to perform preimplantation genetic diagnosis (PGT) to be able to transfer a chromosomally normal embryo. At the same time, we evaluated very carefully the ‘baby house’, meaning the uterine cavity, before any transfer.
The endometrium is a tissue lining the interior of the uterus where the embryo implants and resides during pregnancy. Each month the endometrium prepares for the arrival of an embryo. When this does not occur, menstruation begins. While we used 3D imaging and ultrasound measurements of the uterine lining (Endometrium) thickness, there are still a group of women who experience repeated implantation failures.
A group from Spain (lead by Dr. Carlos Simon; now the commercial test is performed by a company name IGENOMIX) investigated gene activation profile during the ‘window of implantation’, meaning at the specific 12-24 hours when the uterus is receptive and embryo may implant (published first in 2012-2014).
The ERA test uses a small sample of endometrial tissue to find the best day for transferring the embryo. The biopsy is easily and quickly sampled and the results will determine if the endometrium is receptive or not at the time of sampling. The ERA test analyzes the expression levels of 248 genes linked to the status of endometrial receptivity, using RNA sequencing taken from the endometrial tissue. The goal of this test is to find a personalized Window of Implantation to allow for a personalized embryo transfer (pET), optimizing the best time to transfer the embryo and therefore increasing the chance to conceive.
Interim data analysis of a prospective randomized trial, presented in 2016, demonstrated a significant 24% increase in pregnancy rate with pET. When performing the embryo transfer in a personalized way, the chances of getting pregnant are increased after the assisted reproduction treatment. In other studies, the ERA test has resulted in a 73% pregnancy rate in patients with implantation failure.
The uterus needs to be exposed first to 10-14 days of estrogen, and then additionally to progesterone, in order to be ready for embryo implanting = to be receptive. With CB - with our personalized Embryo Transfer (pET) approach, we discovered that she personally needed 2 extra days of progesterone treatment in order for her uterus to be ‘receptive’. We adopted her hormonal treatment according to the ERA test results, she conceived and delivered a healthy son.
For many years, infertility specialists used to investigate ‘implantation failure’ only after at least 2-3 failed embryo transfers. The lack of synchronization between the embryo ready to be implanted and endometrial receptivity is one of the causes of recurrent implantation failure. This is why it is imperative to assess the endometrium in order to determine the optimal day for embryo transfer.