What are the pros and cons of endometrial receptivity tests (ERA, Er-map)?

Laura Garcia de Miguel, MD
Fertility Specialist & Medical Director, Clinica Tambre

Failed IVF Cycles

From this video you will find out:
  • What is endometrium important in fertility treatments?
  • What are the main advantages of using endometrial receptivity tests like (ERA, ER-MAP, Endome TRIO, Endometrial Solution) in fertility treatments?
  • What is ES-TIME test and what kind of information does it provide?
  • What is ES-META test and what kind of information does it provide?
  • What are the limitations or drawbacks associated with endometrial receptivity tests?

What are the pros and cons of endometrial receptivity tests (ERA, Er-map)?

During this event, Dr Laura García de Miguel, Medical Director at Clínica Tambre explored the intricate world of endometrial receptivity tests, focusing on ERA (Endometrial Receptivity Analysis) and ER-map. These tests have gained significant attention and are widely used in assisted reproduction.

The significance of the endometrium

The endometrium is the innermost layer of the uterus, where embryo implantation and fetal development occur. It undergoes significant monthly changes driven by hormonal fluctuations, preparing for potential pregnancies.

For successful embryo implantation, the endometrium must be in prime condition, ideally trilaminar and 8-12 millimeters thick. While embryos are essential in reproductive treatments, a less-than-ideal endometrium can hinder implantation and ongoing pregnancy.

At Clinica Tambre, 2D scans are routinely used to evaluate the endometrium and, if necessary, other imaging tests are used such as hysteroscopy or MRI to assess endometrial morphology. However, endometrial receptivity tests become crucial when facing challenges during treatment.

Receptivity Tests

While fertility clinics may offer various receptivity tests, they all aim to identify the optimal timing for embryo transfer in relation to progesterone, known as the ‘window of implantation.’

At Clinica Tambre, they offer the ‘Endometrial Solution,’ comprising two subtests: ‘ES-Time’ assesses the window of implantation, while ‘ES-Meta’ examines the uterine microbiome for potential infections and imbalances.

Both tests require a biopsy, typically performed by gynecologists during consultation. While not always painless, we recommend taking ibuprofen 30 minutes before the procedure. A full bladder is also advisable.

Biopsy results are usually available within 15 days. It’s crucial to wait for these results before proceeding with endometrial preparation for the next transfer.

ES-Time reveals the patient’s window of implantation, a brief period influenced by estrogen and progesterone levels. Around 25-30% of our patients experience issues with this window, making this test invaluable for tailored transfer planning.

ES-Meta identifies the presence of pathogens and assesses the balance of lactobacillus in the endometrium. This information can lead to antibiotic treatments or microbiome adjustments to enhance pregnancy chances.

Indications for ES-Time and ES-Meta

These tests are recommended when infertility causes are unknown, in cases of implantation failure, recurrent miscarriages, or a history of infections in the uterus.

It’s worth noting that these tests can sometimes yield inconclusive results or require multiple biopsies if the window of implantation isn’t easily identified.


In conclusion, endometrial receptivity tests are essential tools to optimize fertility treatments. Failure to consider them in time can lead to increased costs and disappointment. Choose a trusted clinic that explains all potential strategies, including these tests, and stay well-informed about their necessity and validity periods.

- Questions and Answers

What is the role of progesterone (P4) testing in frozen embryo transfer?

The role of progesterone (P4) testing in frozen embryo transfer is crucial. We need to ensure that before opening the implantation window, the progesterone level is less than one (indicating that the endometrium is not receptive to implantation). Additionally, 24 hours before the transfer, we monitor the progesterone level to confirm that it is high enough. These two tests are routine before opening the implantation window to ensure that the endometrium is not prematurely receptive to progesterone. If we plan to have five days of progesterone supplementation, we need to check, before these five days, that the progesterone level is below one. The day before or two days before the transfer, we confirm that the progesterone level is high enough to avoid additional progesterone supplementation.

I have had 7 failed transfers and I am preparing for the next cycle with a receptivity test in October. How should I schedule IVF after previously undergoing a down-regulated protocol for ERA?

If you’ve had multiple failed transfers, it’s essential to undergo receptivity testing like ERA and other tests, such as EMMA and ALICE, especially if you’re working with Igenomix. It’s crucial to identify any potential issues with your embryos or factors like thrombophilia and coagulation disorders that might require treatments like Clexane or baby aspirin. Additionally, checking the window of implantation and ensuring there are no infections in the endometrium is necessary. Remember, you cannot test these factors on the same day as the transfer; it must be done at least a month before. If everything looks good, you can proceed with the next transfer. If adjustments like probiotics or antioxidants are needed, it might be necessary to postpone the transfer.

What can cause changes in endometrial receptivity, especially adenomyosis?

Adenomyosis can indeed affect endometrial receptivity. Adenomyosis is a condition where glands from the endometrium grow into the walls of the uterus (myometrium). This condition can lead to implantation issues and recurrent implantation failure. While there can be multiple factors influencing changes in endometrial receptivity, adenomyosis is one of the potential causes of altered receptivity in some patients.

Are there any recommended nutrition supplements to increase endometrial receptivity?

Unfortunately, specific nutrition supplements alone are not known to significantly increase endometrial receptivity. Endometrial receptivity is more related to the timing and hormonal environment in the endometrium, and it’s challenging to influence solely through nutritional supplements. However, maintaining a healthy lifestyle and balanced nutrition can support overall reproductive health.

How long is the validity of endometrial receptivity testing (ERA), and when should it be repeated?

The validity of endometrial receptivity testing (ERA) typically lasts for one year. It’s essential to consider that this validity applies when you are following the same treatment protocol. If you change your treatment protocol or strategies, you may need to repeat the ERA test. Always ensure that you are using the same preparation before relying on a previous ERA result.

Are oral probiotics for vaginal microbiome the same as those taken for digestion?

No, oral probiotics for the vaginal microbiome are not the same as those taken for digestion. Specific probiotic strains are designed for different purposes. When addressing vaginal microbiome issues, it’s crucial to use probiotics designed for that purpose to ensure the best results.

Can elevated progesterone levels at the beginning of the cycle indicate anything significant?

Elevated progesterone levels at the beginning of the cycle can indicate a change in ovarian activity, potentially signaling the initiation of endogenous progesterone production. This change in hormone levels may affect the timing and receptivity of the endometrium and could be relevant when planning fertility treatments.

Can adenomyosis prevent implantation?

Yes, adenomyosis can potentially affect implantation and may contribute to recurrent implantation failure. Adenomyosis is a condition where endometrial tissue grows into the uterine muscle (myometrium), which can lead to changes in the uterine environment and impaired receptivity for embryo implantation.

Yes, adenomyosis can potentially affect implantation and may contribute to recurrent implantation failure. Adenomyosis is a condition where endometrial tissue grows into the uterine muscle (myometrium), which can lead to changes in the uterine environment and impaired receptivity for embryo implantation.

Detecting immune factors affecting fertility typically involves blood tests and, in some cases, uterine biopsies. These tests may assess various immune factors, such as natural killer (NK) cell activity and other immunological markers. Immune factors can contribute to recurrent pregnancy loss or implantation failure, and identifying them through appropriate testing can help tailor treatment strategies.

If I have had failed transfers with three months of down-regulation using Lupron, can ERA testing help, or is it necessary to do both?

If you’ve had failed transfers with a three-month down-regulation protocol using Lupron, ERA testing can be beneficial to assess the receptivity of your endometrium. ERA testing evaluates the optimal timing for embryo transfer in your specific case. While the Lupron protocol may help manage certain issues, ERA testing provides more precise information about the timing of embryo transfer and can help refine your treatment approach.

I recently had a receptivity test that indicated I was pre-receptive due to a lack of lactobacillus bacteria in my uterus. How long should I use vaginal probiotics before preparing for a transfer?

When you’ve been found to be pre-receptive due to a lack of lactobacillus bacteria, it’s recommended to use vaginal probiotics for a minimum of two to four weeks before the planned transfer. You should continue using probiotics until the transfer to improve the uterine environment. If your transfer is planned for a later date, it’s advisable to continue probiotic treatment until that time.

Is there a place for intralipids and LMWH (Low Molecular Weight Heparin) in cases of repeated implantation failures?

Yes, intralipids and LMWH can be considered in cases of repeated implantation failures, especially if there are potential immune or clotting factors contributing to the failures. These treatments may help modulate the immune response and improve the chances of successful implantation. However, they should be used based on appropriate testing and clinical evaluation.

Can bacterial vaginosis (BV) affect implantation? Is antibiotic treatment recommended before and after endometrial receptivity testing?

Bacterial vaginosis (BV) can potentially affect implantation, and it’s advisable to address any vaginal infections before proceeding with fertility treatments. Antibiotic treatment before and after endometrial receptivity testing can be recommended to ensure a healthy uterine environment for the embryo transfer.

Apart from blood group compatibility, are there immunological tests to determine the compatibility of a donor with the recipient?

Yes, there are immunological tests that can assess compatibility beyond blood groups between a donor and recipient. These tests can evaluate various immune factors, such as HLA matching and other immunological markers. Compatibility assessments can help tailor donor selection and treatment strategies to maximize the chances of a successful pregnancy.
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Laura Garcia de Miguel, MD

Laura Garcia de Miguel, MD

Dr Laura García de Miguel has worked in the field of gynaecology and obstetrics since 2008. At present, she is a medical director of Clínica Tambre in Madrid, Spain. Dr García de Miguel has extensive experience in IVF and provides a highly personalized approach to each and every patient and custom-tailored treatments to meet the needs of various patients. Dr García de Miguel specializes in treating patients who have had previous IVF failures or who respond poorly to hormonal or IVF treatment. Dr Laura speaks fluent Spanish, English, and French and treats patients from all over the world.
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Caroline Kulczycka

Caroline Kulczycka

Caroline Kulczycka is managing MyIVFAnswers.com and has been hosting IVFWEBINARS dedicated to patients struggling with infertility since 2020. She's highly motivated and believes that educating patients so that they can make informed decisions is essential in their IVF journey. In the past, she has been working as an International Patient Coordinator, where she was helping and directing patients on their right path. She also worked in the tourism industry, and dealt with international customers on a daily basis, including working abroad. In her free time, you’ll find her travelling, biking, learning new things, or spending time outdoors.
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