(Endometrial Receptivity Array)

What is ERA?

ERA stands for Endometrial Receptivity Array or Endometrial Receptivity Analysis.

What is Endometrium?

The Endometrium is the tissue that lines the uterus. It typically thickens in the mid-menstrual cycle in anticipation of an embryo to implant. If the egg is not fertilized or if an embryo does not implant, the uterine lining sheds itself after 14 days, which is when a woman gets her period.

The doctor can observe your endometrial lining with an ultrasound. While this is helpful in measuring how thick or thin your lining is, the ERA test can help provide additional insight into both the environment and the quality of your endometrium. This information can be invaluable when it comes to IVF.

What is Endometrial Receptivity?

The timing between the development of an embryo and the status of the endometrial lining can be key in achieving a pregnancy.

Endometrial Receptivity is the stage in which the Endometrium is prepared to allow the embryo’s implantation.  This stage occurs in a limited time frame named “Window of Implantation”.

The Window of implantation can vary from one woman to another and even a good quality embryo cannot implant if it is transferred when the endometrium is not receptive.

What Exactly is the ERA Test?

Endometrial receptivity array (ERA) is a diagnostic procedure that may help determine whether the Endometrium is ready for embryo implantation.

How is it done?

It typically begins 1-1 ½ months prior to a frozen embryo transfer (FET).

The woman will be prescribed sequential hormones, including estrogen and progesterone in advance of the procedure, as she would in preparation for a frozen embryo transfer (FET). An endometrial biopsy is performed on the standard embryo transfer day (in lieu of an actual embryo transfer), when the window of implantation is expected to occur.

The biopsy is a straightforward, outpatient procedure with minimal discomfort. During the biopsy a small instrument called a pipelle is inserted through the vagina into the uterus. The doctor will use the pipelle to “scratch” the uterine lining and obtain a small amount of tissue for testing. Some women experience cramping or light bleeding during or after the procedure.

The sample will be sent to a lab where molecular analysis is completed to determine the best time to attempt embryo implantation in a future  embryo transfer cycle.

There are three potential results:

Pre-receptive: The lining is not yet ready to receive an embryo, and implantation is less likely to occur.

Receptive: The lining is ready to receive the embryo, which is most likely to implant.

Post-receptive: The lining has already reached the stage for optimal embryo implantation but is no longer in that stage. The embryo is less likely to implant at this time.

A Personalised Embryo Transfer is then done in a FET cycle according to your implantation window.

This increases your chances of a successful pregnancy.

Who is ERA recommended for?

ERA biopsy is an option for women undergoing infertility treatment and is typically recommended for:

  • Women who have had previous IVF cycle failures.
  • Women who have very few embryos available for transfer and need to maximize their chances for each embryo.

The ERA endometrial biopsy is not part of a female fertility evaluation and is not typically recommended for first-time IVF patients. However, it’s always important for women to discuss their personal situation with their doctor.