ERA (Endometrial Receptive Array)


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ERA (Endometrial Receptive Array)

An endometrial receptive array is a test done on women who are going through IVF procedure.  The test helps to determine the optimal timing for the embryo implantation and is primarily used in those women who undergo repeated implantation failure following the embryo transfers.

What is Embryo implantation and when does it fail?

In a natural pregnancy, the sperm fertilizes the egg to form an embryo.  This process takes place in the fallopian tubes.  The embryo then travels to the uterus and gets implanted in the endometrial or uterine lining.
In the case of IVF, the embryo is created in the lab.  Once the embryos are transferred to the uterus of the expecting mother, implantation occurs.  The endometrial lining will thicken and become receptive to the implantation of the fertilized egg.  The oestrogen and progesterone hormones are secreted by the ovary which prepare the lining.

Endometrial Receptive Array Test in Chennai

Implantation might fail due to:

  • Asynchrony between the endometrium and the embryo.
  • Lack of required endometrial thickness and vascularity.
  • Scarred endometrium called Asherman’s Syndrome due to repeated iatrogenic Dand C procedures.
  • Endometrial infections like TB

The process is quite complex and requires proper alignment of a plethora of morphological, biochemical and genetic factors.  There is also the need for biochemical communication between the embryo and uterine lining.  A woman going through IVF received oestrogen and progesterone to assist in the thickening of the lining.

When is the ERA used?

About 25% of the patients who go through recurrent failed embryo transfer experience a lack of coordination between the embryo and endometrium.  The ERA test helps to determine the window very precisely.  It would improve the chances of pregnancy for women who are undergoing IVF.  The test is only recommended when someone goes through repeated implantation failures.  The assessment from the test would allow the doctors to pinpoint the best day for the transfer procedure.

How does ERA Work?

The ERA tests the receptivity of the endometrial  lining and determines the optimal timing for transfer of good quality embryos.  The  test consists of an endometrial biopsy where a small sample of the tissue is collected painlessly.  The optimal timing for hormone administration and embryo transfer is determined.  The general protocol is to transfer the embryo on day-5 of growth, but this estimate is not accurate for one in every  4 people.  The embryo transfer must occur earlier or later in some, which is why the ERA test becomes necessary. 

The test results would either show the endometrial lining to be “receptive” or “non-receptive”. It will also tell us if it is non-receptive whether it pre or post  receptive.  Prereceptive endometrium indicates that the endometrium needs to be transferred earlier and post-receptive endometrium, later than the expected day of transfer.  This helps the doctors to transfer a good quality embryos during the implantation window and increase the overall success rate of IVF procedure.

The test is selectively offered couples with repeated implantation failures.

Authored by Dr. Radhika Meka

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