What is an era, you’re asking?

Endometrial receptivity analyses have been helpful to reproductive medical specialists seeking to identify the reasons why normal embryos fail to implant.

We know that certain uterine abnormalities can cause failures, and implantation failure appears to be one factor. In preparation for implantation, the endometrium undergoes dramatic growth during the menstrual cycle due to the rise and fall of ovarian hormones.  

If you face an implantation failure and think that your uterus is defective or your body is not accepting the embryo, then keep in mind that it’s not your fault. Many women who undergo IVF failure think the same. 

This article will help you understand what causes repeated implantation failure and what the culprit might be.  

What is endometrium? 

The endometrium is the lining of the uterus that is composed of numerous glands. It is a part of the female reproductive system that plays a vital role during the pregnancy. Endometrium or endometrial lining is the tissue that serves as “wallpaper” of the uterus.  

The endometrium is made up of mucosal tissues and has two layers.

The first layer is known as stratum basalis. It is attached to the smooth muscle tissue of the uterus called the myometrium.

The second layer is dynamic and changes in response to the menstrual cycle. It is called the stratum functionalis or functional layer. It is a part of endometrium where a blastocyst (fertilized egg) implants if conception takes place. 

What is implantation failure? 

An embryo is formed when an egg and sperm unite together. The embryo then divides rapidly and reaches the uterus in the blastocyst stage. The blastocyst starts communicating with the endometrium in the uterus by secreting certain compounds. If the embryo is competent and the endometrium is receptive, it results in implantation. 

Implantation is the attachment of a blastocyst embryo with the endometrial lining that further develops into a fetus. If a woman undergoes three or more in vitro fertilization (IVF) failure, or if implantation does not happen after transferring 10 viable embryos, then the woman has an implantation failure. 

When an embryo fails to implant, it may be due to an unhealthy embryo or a non-receptive endometrium. The role of the endometrium is like soil quality in agriculture. What happens when you plant a fertile seed in unhealthy soil? It fails to grow. 

What is an ERA test? 

The term “ERA” stands for Endometrial Receptivity Analysis or Endometrial Receptivity Array. It is a genetic test to identify the implantation window and find the best time for embryo transfer.

To run an ERA test, a small sample of a woman’s endometrial tissue is taken to assess if the endometrial lining is properly developed.  

The ERA test is done using the latest technology and analyzes the expressions of 236 genes per sample to determine the time for implanting the embryo. The menstrual cycle of every woman has an implantation window. It’s a small window of optimal time during which the uterine lining reaches the perfect implantation state.  

The implantation window lasts for a few days, usually from the 19th day to the 23rd day of the menstrual cycle. 80% of the women have this window at the expected time, and 20% have a unique window that occurs earlier or later than the expected time.

During the IVF treatment, it is important to determine if the window is open or closed before transferring the embryo, to avoid implantation failure. 

How is the ERA test performed? 

A tissue sample of the uterine lining is taken for an ERA test, which is then injected through the cervix. Suction is created to draw out the sample from the uterus lining. The sample is sent for analysis using the Next Generation Sequencing technology (NGS).

This test does not require anesthesia, but progesterone supplements are given for 5 days before taking the sample for testing. Progesterone is the hormone that plays a vital role to make the endometrium receptive to an embryo. This hormone is administered for 5 days during the IVF cycle before implantation.  

The genetic material of endometrium has a unique expression when it is receptive. If the tissues are non-receptive, you need to perform the test again until you find the perfect implantation window. 

Who should consider an ERA test? 

An ERA test can be beneficial for those who have had 3 or more unsuccessful IVF cycles despite having a normal endometrial thickness and uterus. The test results by a computational predictor determine whether the patient’s endometrium is receptive or unreceptive.

If the endometrium is non-receptive, it means the implantation window is displaced. A displaced non-receptive implantation window has been detected in 20-25% of patients. 

Before going for an ERA test, it is better to discuss with your doctor to find if it’s right for you regarding your fertility history. ERA test is for: 

• Patients who have a thin endometrial lining 
• Patients who have had multiple biochemical pregnancies 
• Patients who have had more than two unsuccessful embryo transfers 
• Patients who have had implantation failure despite high-quality embryos  

How much does an ERA cost? 

The ERA test incurs extra charges to the standard cost of your IVF treatment. This test uses advanced technology, so the cost is relatively high. However, it may significantly increase the chances of success and does not seem an unreasonable cost. The cost of the ERA test varies depending on the geographical location and clinic.  

The approximate cost of the ERA test in different regions is as follows: 

• In the USA, it is between $750 and $1000. 
• In the UK, it is between £1200 and £1500 
• In Europe, it is between €800 and €1200.  

Final Thoughts 

The ERA test has been proven to improve global pregnancy rates up to 73% during personalized transfers.

If you feel an ERA biopsy can work for you, consult our SurrogateFirst team or professional surrogacy resources page. Infertility treatment is continuously evolving, and the medical team is always there to find out what would work best for you. 

If you and your medical consultants feel that the ERA test can improve your chances of success, it is advisable to go ahead with it. It is a relatively easy and simple test that provides you with the information needed to plan your embryo transfer and improves the chances of IVF success.