Personalized Embryo Transfer (PET)
What is Personalized Embryo Transfer?
It is test to identify the window of implantation using ERA test to increase the chances of implantation for a individual with repeated implantation failure.
What is Window of Implantation?
The window of implantation is defined as that period when the uterus is receptive for implantation of the free-lying blastocyst. This period of receptivity is short and results from the programmed sequence of the action of oestrogen and progesterone on the endometrium. Implantation starts with an exchange of biochemical signals between trophoblast and the endometrium resulting in attachment of the embryo and decidualization of the uterus. This period is short and for a successful implantation, it is important to know the exact window of implantation for embryo transfer for optimum results. Presently, there is no method of knowing the window of implantation.
Fortunately, Scientist working on this problem has devised a new test for determining the window of implantation. It is called ERA test.
What is ERA (ERA stands for Endometrial Receptivity Analysis (or Array) Test?
It is a test to determine the window implantation in cases of recurrent or repeated implantation failure when everything else seems to be going well. The ERA test is one of the new developments, which is offering new hope to patients coping with implantation failure. It is a genetic test which uses a small sample of a woman’s endometrial tissue to evaluate whether or not the endometrial lining is prepared to accept an implanting embryo. During this receptive period, Proteins are created which make the lining thicker and more receptive. In about 84% of women, this small window occurs at the expected time.
However, in about 16% of women have a unique window which can be earlier or later than expected. For IVF cycles, this could mean that the embryo transfer is happening on the wrong day, when the window hasn’t opened yet or has already closed, thereby causing implantation failure. This test compares the RNA of the receptive period with the non receptive period. This test is performed with a small endometrial biopsy at a very special time of the cycle to find the RNA profile of the biopsy and compared with the database created during other parts of the IVF cycle.
This test is done only for patients with repeated implantation failure. The time of biopsy is important for this test.
What Do You Need to Know About ERA?
- Reasons for Implantation failure?
There can be several factors which can cause implantation failure. Most fall under two categories.
- Genetic abnormalities: Most common issue is genetic or chromosomal problems with the embryo, specially older women using their own eggs. Ageing eggs have a much higher rate of chromosomal abnormalities. This explains why implantation rates go down as the patient age goes up. sometimes, there can be a genetic problem with the sperm. The first line of treatment is to go for PDS (Pre-Implantation Genetic screening). This can improve the implantation rate. Next recommendation is to go for egg donation.
- Uterine receptivity problems: If there is no genetic reason for implantation failure, then we should look for uterine receptivity. For this there can be several reasons:
- Anatomical problem with the shape or position of the uterus
- Hormonal Imbalance or disorder of thyroid and other fertility hormones
- Autoimmune function compromised
- Endometrial lining compromised
There are many tests to narrow down the problem, and ERA test is one such test