Endometrial Receptivity Analysis (ERA) The Importance of Timing Accuracy

What Is the ERA Test?

In every IVF cycle, the timing of embryo implantation is one of the most crucial factors for success. It's not enough for the embryo to be of good quality and the uterus to be healthy. Implantation success also depends on the receptivity of the endometrium during the window of implantation (WOI). The ERA test is an advanced diagnostic tool designed to answer this exact question: when is the most appropriate time for embryo transfer?

The ERA (Endometrial Receptivity Analysis) is a molecular test that evaluates the functionality of the endometrium by analyzing the expression of hundreds of genes related to its receptivity. It is a highly accurate tool that allows specialists to determine whether the endometrium was receptive or not at the time of biopsy.

This means we can identify the so-called implantation window (WOI) in a personalized manner and adjust the timing of the embryo transfer to match each woman’s specific needs—maximizing the chances of success.

Why Is the Implantation Window Test (ERA) Recommended

In many cases where everything appears normal egg quality is good, the uterus is healthy, and the embryo is viable—pregnancy still does not occur. One of the possible reasons investigated is that the embryo transfer may be performed outside the optimal implantation window.

The ERA test (Endometrial Receptivity Analysis) is mainly recommended for women who have experienced recurrent implantation failure (RIF) during IVF cycles, without any other obvious cause. In these cases, evaluating the implantation window often provides critical information that helps adjust the treatment strategy and optimize the timing of embryo transfer.

How the ERA Test Is Performed

The procedure involves preparing the endometrium with the same medication protocol that a woman would receive during an embryo transfer cycle. On the appropriate day, based on the number of days of progesterone exposure, an endometrial biopsy is taken.

The sample is then sent to a specialized laboratory, where the expression of specific genes related to endometrial receptivity is analyzed in order to determine the implantation window.

The results show whether the endometrium was:

In the receptive phase – meaning the implantation window occurred at the time of biopsy

In the pre-receptive or post-receptive phase – meaning the implantation window lies at a different time point

What Is the Importance of the ERA Test Result

The significance of the ERA result lies in the ability to accurately plan the next embryo transfer. If the endometrium is found to be pre-receptive, progesterone will be administered for more days. If it is post-receptive, fewer days of progesterone will be given. In this way, endometrial receptivity is assessed, and the timing of embryo transfer is tailored—not based on general guidelines, but on the specific needs of each woman’s endometrium.

The Use of the ERA Test by the Scientific Community

Although the ERA is not a routine diagnostic test for all IVF cycles, several studies confirm its value in cases of unexplained implantation failure, when everything else appears normal. Its use has been associated with improved success rates in women with a displaced implantation window. However, it is essential to apply the test with clinical judgment, as part of a comprehensive and personalized evaluation.

The FertUlity Approach

At FertUlity, we carefully evaluate which couples or women can truly benefit from the ERA test. We do not rely on standardized protocols, but on a holistic assessment of each medical history. When indicated, we combine the ERA with additional endometrial tests (e.g. ALICE, EMMA) in order to accurately map the microbial and inflammatory status of the uterine lining.

Our goal is not simply to perform an embryo transfer, but to transfer the embryo at the right time, in the optimal environment, with the highest chances of success. If you have experienced implantation failures without an obvious cause, ERA may be the next step toward a more targeted and personalized fertility approach.

Frequently Asked Questions About ERA Test

When is it recommended to do the ERA test?

ERA is mainly recommended for women who have experienced two or more failed embryo transfers (RIF) with good-quality embryos and no identifiable cause. In such cases, assessing endometrial receptivity at the time of transfer can be a key factor.

Does the ERA biopsy hurt?

The endometrial biopsy is similar to the experience of a Pap test (PAP test) or an embryo transfer. It may cause brief and temporary discomfort, but the procedure lasts only a few minutes and does not require anesthesia or hospitalization.

Are there any side effects?

The ERA test is a safe procedure with minimal side effects. Some women may experience light bleeding or mild cramping for a few hours after the biopsy.

If the result shows I’m “pre-receptive,” what does that mean for my next IVF cycle?

If the result shows that the endometrium was receptive before the implantation window, then the next embryo transfer cycle will be scheduled with additional days of progesterone, so that the transfer takes place at the correct timing.

Do I need to do ERA in every cycle?

No, once the ideal implantation window has been identified, the results are valid for future cycles with a similar hormonal protocol. The test does not need to be repeated unless there is a significant change in protocol or endometrial condition.

Our Doctors

In an era where fertility requires knowledge, care, and substantial guidance, FertUlity is not an impersonal clinic. It is two people who look you in the eye and accompany you step by step on the journey you dream of.

Dr. Chrysostomos (Makis) Papadopoulos Obstetrician – Gynecologist, MD, PhDc, MIC I

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Dr. Chrysostomos Papadopoulos - Specialist in Infertility, Endocrinology & Menopause in Athens

Dr. Maria Oikonomou Obstetrician – Gynecologist

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FertulityThrough the Words of our Parents

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      EXCELLENT  
   Based on 12 reviews 
    
 
 
 
   
 
 
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   Μαρια 
 26 days ago
 
 
  The word "thank you" to Dr. Makis Papadopoulos is too small to describe the gratitude we feel for this man. I am pregnant after IVF, having succeeded on the first attempt, and we owe this exclusively to our doctor. First Contact & Communication: From the very first contact, he won us over with his kindness, enthusiasm and willingness to dedicate as much time as we needed. Willing to explain everything in every detail, he solved every question we had in depth — not even a professor to students would analyze them with such patience and contagiousness! Scientific Training: He is an excellent scientist, with deep knowledge of the subject, a perfectionist and focused professional who leaves absolutely nothing to chance. He designed the right treatment for us, solving every problem down to the last detail, making us feel that whatever problem arises, it is certain that it will be solved. HUMANITY & SUPPORT: The most important thing, however, is his humanity. Communication with him was Immediate and he always had as much time as you needed on the phone to solve every question. He showed a deep, real interest, embracing us not just as a doctor, but as if he were our brother. We highly recommend him to every couple starting this journey. He deserves blind trust! We thank you from the bottom of our hearts for the greatest miracle of our lives!

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   Alexandra 
 52 days ago
 
 
  I don't often write reviews, but I feel that Mr. Makis truly deserves it. From the very first moment, he made me feel safe and confident. He listened carefully to what was on my mind, answered every question I had, and explained everything in a simple way, always based on scientific data. Many times, he even sent me relevant scientific studies so that I could better understand why he was suggesting a particular approach. But what stood out to me the most was that he didn't stop at the appointment. He followed up, was genuinely interested in my progress, and was available when I needed him. This is something you rarely encounter. Fortunately, he returned to Greece. He is one of the few doctors who, beyond their knowledge, remain above all human beings. He makes you feel like he sees you as a person and not as just another incident.

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   Matina 
 69 days ago
 
 
  A big thank you to Dr. Makis Papadopoulos who supported us from day one, who checked every little detail, who explained to us every move-step, every test, every medication for the reason we were doing it and what we would achieve. With incredible experience, knowledge, a lot of patience (because we had two other failed attempts with another doctor) and trust, within 8 months he adapted the protocols for our case and we achieved the positive result and we hold in our arms a priceless diamond. Above all, a rare person, calm and always available to listen to our concerns and reassure us. I highly recommend him!

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   Eva 
 93 days ago
 
 
  Thanks to Dr Makis Papadopoulos, I am now holding my two beautiful babies in my arms! He is a true expert. Professional with a human centric approach, friendly and empathetic, always available to answer our (many many) questions. I trust Dr Makis blindly and, honestly, I cannot recommend him enough!
  
 
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   Ivy 
 100 days ago
 
 
  My experience with Dr. Makis took me from a clinical stagnation to an incredible breakthrough, highly recommend Dr. Makis! Navigating the exhausting world of IVF, you know how devastating it is to watch your protocol dosages go up while your results go down. After three intense, high-dosage cycles with a previous clinic, I was left feeling incredibly discouraged. Despite escalating medications and growth hormones, my blastocyst yield was dwindling, culminating in a heartbreaking round with zero blastocysts. I knew I needed a doctor who didn't just follow a standard script, but who truly understood the nuances of egg quality and customized protocols. That is when I found Dr. Makis. Dr. Makis completely revolutionized my treatment plan. Instead of just pushing maximum dosages, he took a highly strategic, tailored approach. The result? Quality over pure protocol size. While my previous doctors kept increasing the medication dosages (which yielded fewer or zero blastocysts), Dr. Makis completely changed the strategy. He lowered the heavy stimulation, introduced smart egg-quality support (like melatonin), changed the protocol style entirely, and achieved a 700% increase in blastocysts compared to my best previous rounds. Beyond the incredible results, Dr. Makis brings a level of expertise, precision, and reassuring care that is rare to find. He looks at you as an individual, not a statistic, and knows exactly how to pivot when traditional routes fail. If you are looking for a specialist who can turn a difficult prognosis into an overwhelming success, look no further than Dr. Makis. I am incredibly grateful for his care.
  
 
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   Olga 
 111 days ago
 
 
  Dr. Makis Papadopoulos was excellent, professional, and very reassuring throughout the entire process. Thanks to his expertise and guidance, we were able to identify the issue early and take the appropriate steps from the beginning. He took the time to explain everything clearly, answered all our questions with patience, and made us feel comfortable and confident throughout our journey. We truly appreciated his caring approach, professionalism, and dedication. Highly recommended!
  
 
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   Euaggelia 
 122 days ago
 
 
  Dr. Makis Papadopoulos is an excellent scientist and above all a rare person! He is an approachable and smiling doctor, with excellent medical knowledge, who from the first moment I met him made me feel comfortable and trust him completely, answering every question I had with patience and documenting every answer with scientific studies and articles! The most important thing, however, is that Dr. Makis Papadopoulos is always there on the other end of the line to listen to you and reassure you without a trace of haste, a doctor who truly cares and makes you feel like he is your own person! Makis, thank you very much for everything!!! I am very lucky to have met you!

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   Anastasia 
 129 days ago
 
 
  Dr. Makis Papadopoulos is an excellent scientist with a human-centered interest. Our collaboration was excellent from the very beginning and he made me feel confident and secure by explaining every step of the process in great detail. I highly recommend him!

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   Fay 
 131 days ago
 
 
  Dr Makis Papadopoulos is very professional, caring and attentive. Very thorough in explaining the whole process throughout every step. Thank you! Highly recommended!!
  
 
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   Christina 
 134 days ago
 
 
  I would like to share my experience with Dr. Makis Papadopoulos, an outstanding gynecologist and scientist. We first connected in the summer of 2024, while he was based in Germany, through a mutual acquaintance, following a particularly challenging period for us. Prior to meeting him, we had gone through repeated unsuccessful attempts of stimulation and fertilization with other gynecologists. Unfortunately, those approaches relied largely on standardized protocols, without sufficient personalization to address the specific needs of my case. From the very beginning, Dr. Makis stood out for his human-centered approach and his willingness to dedicate time to truly understand our situation in depth. With strong, up-to-date scientific knowledge, he approaches every case holistically, focusing on individualized treatment and adapting protocols to the patient's unique needs. Throughout our collaboration, which now spans approximately two years (with a few breaks on our side), he has consistently been available, supportive, and clear in his guidance. He inspired confidence and helped us stay positive even during difficult phases of the journey. Beyond his scientific expertise, what truly sets him apart is his genuine care for the person behind each case: his empathy, honesty, and continuous effort to achieve the best possible outcome. My husband and I are deeply grateful for his support and guidance, and we now feel ready and optimistic to move forward to the next final stage. We highly recommend him to anyone seeking a gynecologist with true expertise, professionalism, and compassion. I would like to share my experience with Dr. Makis Papadopoulos, an excellent gynecologist and scientist. We met in the summer of 2024, when he was in Germany, through a mutual acquaintance, after a particularly demanding period for us. Before meeting him, we had gone through repeated failed attempts at stimulation and fertilization with other gynecologists. Unfortunately, the approaches that had been followed were mainly based on standardized protocols, without the necessary individualization to the specifics of my case. From the beginning, Dr. Makis stood out for his human approach and his willingness to spend time to understand our case in depth. With modern knowledge and scientific training, he approaches each issue multidimensionally, emphasizing the individualization of treatment and adapting the protocols to the real needs of the patient. During our collaboration, which now spans about two years (with short breaks on our part), he was always available, supportive and clear in his guidance. He inspired confidence in us and helped us remain optimistic even in difficult phases. In addition to his scientific competence, what sets him apart is his genuine interest in the person behind each case: his empathy, his honesty and his constant effort to achieve the best possible outcome. My husband and I thank him warmly for his support and guidance and we now feel ready and optimistic to move on to the next final stage. We highly recommend him to anyone looking for a gynecologist with real knowledge, professionalism and humanity.

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   Faidra 
 135 days ago
 
 
  Dr. Makis Papadopoulos is an excellent gynecologist and above all an excellent person! I truly thank him for his support and care during the egg freezing process. Although my case was particularly demanding, he stood by me with patience, knowledge, great experience and real interest. Our communication was direct and human, while his availability at the many appointments made me feel safe at every step. The protocols were designed specifically for me, aiming for the best possible result, while also taking into account the cost of the medications. I recommend him with all my heart to every woman who wants to trust someone for something so important and sensitive for her.

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   Iliana 
 137 days ago
 
 
  I highly recommend Dr. Makis, he is an incredible specialist. My journey was far from easy, encountering several challenges that  made the process feel overwhelming at times. What sets him apart is his willingness to go beyond standard procedures. He developed a specialized, custom protocol, tailored to my situation, which ultimately made all the difference. Beyond his technical expertise, his calm and clear communication kept me grounded throughout the process. I am so grateful for his persistence and high level of care!

Why choose FertUlity?

Because every fertility journey deserves the right support. At FertUlity, we provide science-based fertility care with a human approach. We support every path, from fertility assessment and preservation to modern assisted reproduction.

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