Fertility Treatments

Endometrial Receptivity

It is a genetic testing technique that evaluates gene expression to see if the endometrial lining is developed enough to receive the embryos.


IVF or in vitro fertilization is considered the most successful artificial reproductive technique or ART for infertility among almost all age groups worldwide. But the failure of embryo transfer through IVF can be quite frustrating and disheartening for all parties involved, including the patients and the doctor. 

While looking for the reasons and answers for the failure, you tend to think of the transferred embryo (created by the egg fertilized with the sperm) and the environment in which the doctor transferred it into the uterus.

But in the past few years, several pieces of research have shown that an embryo’s failure to implant may not just be due to the quality of the embryo created by fertilization but also due to some problems associated with the endometrial lining. The endometrial lining is a soft tissue inside your uterus that prepares for the embryo to implant every month. 

That’s why even though your embryo may be healthy and of high quality, you may suffer failure in IVF due to failure in implantation. 

The endometrial lining is considered an integral part of a successful pregnancy as that is where the embryo implants in the uterus. The doctors usually assess it with the help of an ultrasound. Unfortunately, until a few years ago, there wasn’t much reliable testing about endometrium that could help us determine the receptivity of the endometrial lining to improve the chances of successful embryo implantation. 

But nowadays, if you have experienced two or more IVF attempt failures even with good-quality embryos, the doctor will most probably recommend you the endometrial receptivity analysis. In addition, if you have suffered multiple miscarriages, you may want to have a consultation with your doctor about the pre-implantation genetic testing for aneuploidy. This testing may help you increase the chances of a successful pregnancy and healthy childbirth.

What Is ERA?

Endometrial receptivity analysis or ERA is a genetic testing technique to evaluate the expression of genes to determine whether or not the endometrial lining is developed enough to receive the embryos. The latest scientific technology for this test analyses the expression level of 236 genes to provide an assessment of optimal timing for the placement of embryos in your uterus to achieve successful implantation. The window of opportunity is relatively small for the placement and is accurate in around 80% of the women. 

Experts, after years of research on over 12,000 specimens, have found that approximately 1 in every 5 women (20%) has a unique window (when the implantation can be most successful), for which the protocols and timeline of embryo transfer need to be altered completely, to achieve a successful pregnancy. It is usually achieved by adjusting the timing of medications administered to make the pregnancy successful. 

Endometrial receptivity analysis has probes for the 236 different genes hybridized with the RNA or ribonucleic acid. First, the doctor performs an endometrial biopsy procedure to collect a tissue sample from your uterus for analysis. Then, a computerized predictor reads the signal intensities to classify them as “receptive” and “non-receptive”. 

The ERA testing can help the doctor determine if they need to change the embryo transfer timing based on your result.

How Is This Test Done?

The doctors perform a mock programmed cycle with natural estrogen for approximately two weeks and then add natural progesterone for five whole days (progesterone in oil (PIO) and/or vaginal). When it comes to endometrial receptivity analysis, a biopsy is performed at luteinising hormone surge for more than seven days during your natural cycle and progesterone + 5 days during your hormone replacement cycle. 

During the biopsy, your uterine lining is scratched for around 10 seconds to collect the tissue sample, which may be painful for approx. 10 to 30 seconds. The doctor may provide you with a non-steroidal anti-inflammatory drug about an hour beforehand to prevent and reduce cramping. You may want to come with a designated driver if you take an anxiolytic drug to relax. Then, the sample will be sent to a lab for analysis on 236 different genes associated with endometrial receptivity. 

One of the queries frequently raised by our patients at Siya Health about ERA is whether it is painful. An ERA is a minor procedure that can be completed in the doctor’s office or clinic itself. During the procedure, you may experience slight discomfort while the sample is being retrieved. But you can always take OTC medications to alleviate the pain and discomfort.

How Does An ERA Test Work?

In this test, your doctor performs an endometrial biopsy in a mock embryo transfer cycle before starting your FET or IVF cycle. The sample tissues will then be analyzed to check the endometrial receptivity and determine the optimal timing of embryo transfer. There will be three potential results of the test: 

  • Pre-receptive: It indicates that your endometrial lining is not quite ready for embryo implantation. So the transfer timing is not ideal.
  • Receptive: It indicates that your endometrial lining is ready for implantation at the time of the test. 
  • Post-receptive: It indicates that your endometrial lining was once ready for embryo transfer and implantation, but now it has gone past the optimal timing. 

After the results for your ERA test are ready, they will be sent to your doctor so that they can make the necessary changes in the IVF protocol and timeline to make the embryo transfer when your endometrial lining is ready for implantation.

Should You Consider An ERA Test?

Suppose you’ve just started the conception process, or haven’t yet had a miscarriage, or it’s your first time going for IVF. In that case, it will be quite early for you to think about endometrial receptivity analysis. So during your first consultation, the doctor will first look at your ovarian function and reserve. Then, they will assess your uterine lining, uterus and ovaries with the help of an ultrasound. But they will only do it if they feel it’s necessary. 

If you have experienced two or more IVF attempt failures even with good-quality embryos, the doctor will most probably recommend you the endometrial receptivity analysis.

Risks And Limitations

Endometrial receptivity analysis is considered the best diagnosis to determine the optimal timing of embryo transfer for implantation if you have opted for assisted or artificial reproductive techniques like IVF. A tissue called endometrium is situated in the interior of your uterus, which is prepared by your body to receive the embryo for implantation. The endometrium is where your embryo stays during the gestation period. Therefore, there is a particular window of implantation that may convert into a successful pregnancy. 

The doctor will first perform an endometrial biopsy at the doctor’s clinic or office for the ERA test. Therefore, it would be best if you discussed the risks associated with it during the consultation. 

The receptive result provided by the ERA can not provide you with a guarantee for pregnancy after embryo transfer. Also, this test won’t tell you about any other endometrial pathologies or the quality of your embryos.

Abnormal Test Results

In around 90% of the cases, the doctors can successfully recommend the optimal timing of embryo transfer. As for the remaining ones, the doctor will ask you to go through the test again. The report of your endometrial receptivity analysis test will provide you with a definite answer as to whether you should go for the embryo transfer or repeat the test. 

Usually, the doctors recommend repeating the test in case of inconclusive results, around 5% of the total cases. 

Having a conclusive ERA result will provide you with some definite answers about your infertility (if so), or you will be able to determine whether your embryo transfer timing was not right, due to which you weren’t able to get pregnant. But, more importantly, this test will provide you with a more suitable time when you can go through with embryo transfer to convert it to a successful pregnancy.

Is The ERA Test Covered Under Insurance?

If you have not been able to conceive for a while, have had multiple miscarriages, or have had multiple failed IVF attempts, you may consider going for ERA. In that case, you may want to get in touch with your doctor about it. Although the cost of endometrial receptivity analysis may vary from clinic to clinic, it may not be covered by insurance. That’s why speaking to your doctor would be the best idea, so that you can prepare your budget in due time. Although you may consider this test as an added expense, it will help you improve the effectiveness of your IVF attempt and result in a successful pregnancy. 

Millions of people have benefitted from having their endometrial lining analyzed with the help of endometrial receptivity analysis. This test will help you determine whether or not your endometrial lining is developed enough to receive the embryos for implantation.


Endometrial receptivity analysis or ERA is a diagnostic test used to analyze your endometrial lining and determine whether or not it is ready to receive the embryos for implantation. This test evaluates the gene expression levels of 238 different genes associated with the endometrial receptivity to determine the optimal timing for embryo transfer. 

The ERA test may be recommended to you by the doctor if you have not been able to conceive a child for a while, experienced multiple miscarriages, or have had multiple failed IVF attempts. Although it is not a necessary diagnostic test, it may help you find out why you have not been able to get pregnant even after having good quality embryos. 

If you are looking to find more information on endometrial receptivity analysis or ERA, please consult the Fertility experts at Siya Health, or call our Siya Fertility Counsellor today.

Meet Our Fertility Specialists

Dr. Dipesh Sorathiya

M.S. (Obs & Gyn)
DIP. in Gynec Endoscopy (CICE)

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