What is the ‘implantation window’ in fertility treatment and how to improve it?

Susanna Malkhasian, MD
Gynaecologist & Fertility Specialist, UR Vistahermosa
Evangelos Papanikolaou, MD, PhD
Founder & Reproductive Medicine Specialist, Assisting Nature – Human Reproduction & Genetics
Halyna Strelko, MD
Co-founder& Leading Reproduction Specialist, IVMED

Embryo Implantation

From this video you will find out:
  • How do we define the window of implantation, and why is it crucial for pregnancy?
  • What is the ERA test, and how does it assess endometrial receptivity? When is it recommended for patients?
  • What is the ideal thickness for the endometrium before embryo transfer, and how does it impact the success rate?
  • What additional tests are recommended for patients with repeated implantation failures despite good endometrial thickness and embryo quality?
  • What are the current perspectives on using PRP (Platelet-Rich Plasma) for improving endometrial thickness, and what are the considerations for its use?

What is the ‘implantation window’ in fertility treatment and how to improve it?

Many people working in IVF have spent a great deal of time and effort researching the embryo and not so much the endometrium or lining of the womb where the embryo implants. In the past 15 years or so, there’s been a great deal of research into implantation. If you think of the embryo as the seed and the endometrium as the soil, it’s clear that to grow a healthy plant, or in this case, a healthy pregnancy, you need both a good seed (healthy embryo) and good soil (healthy and receptive endometrium).

Our guests were invited to help you better understand what is the implantation window in fertility treatment and how to improve it.



- Questions and Answers

What’s the window of implantation how can we identify it, and why is it important? What can we do to assess endometrial receptivity before embryo transfer?

Dr Evangelos Papanikolaou, Assisting Nature: The window of implantation is very crucial because it renders the female partner of a couple, and particularly humankind, not able to become pregnant at any certain point of the cycle. So, it’s only a defined period after ovulation that we can become pregnant. Otherwise, like other animals, we would become pregnant very easily. The implant of the window of implantation is very difficult to define exactly. But as a general idea, after different studies since 1956 in the United States, it has been defined as 5 to 8 days after ovulation. This is the first point regarding physiology, and the things that we might discuss today are whether there exist, women who have a different window of implantation, whether doctors with our stimulation alter the window of implantation, or if we can improve the window of implantation with any medication that can be administered in the luteal phase.

Dr Halyna Strelko, IVMED Fertility Center: I would like to start with the old method of implantation window study. It was quite an old method and concerned histological study and electronic microscopic study of the endometrium and some morphological findings. However, approximately 10 years ago, a different method was discovered to evaluate endometrial receptivity, and now it is more often used. This method is called the ERA test (Endometrium Receptivity Assessment Test). Authors of this method studied different gene expressions in the endometrium at different times of progesterone taken after 5 days, after 7 days of progesterone, and after 3 days of progesterone, and then discovered some gene expression which should be at the time when the endometrium is ready to receive embryo and when the embryo has the maximum chance to implant in this endometrium. And now, this is the more modern and the best way to assess endometrial receptivity. This test is not for all women. Normally, there should be a minimum of 1 or 2 unsuccessful transfers with good-quality embryos, and this is crucial because if the quality of embryos is not very good, the first problem is embryo quality.

We can consider implantation issues only in cases when we have very good embryo quality. In such cases, it’s necessary to prepare the endometrium as if we were planning for the transfer. There may be two ways to prepare the endometrium: replacement hormonal therapy, which involves artificial hormonal cycles, or the natural cycle, sometimes modified. Then, after 5 days of progesterone in a replacement hormonal therapy cycle, or after 7 days following LH Peak or HCG injection, we can take a sample of about 1 mm of endometrial tissue from the uterus. This sample is sent to a genetic laboratory, where the gene expression is compared with what is expected at that moment, providing an answer on whether the endometrium is receptive, pre-receptive, or post-receptive.

What’s more important, embryo or endometrium quality? On average, how do you rate the importance of the embryo compared to the endometrium for the average patient?

Dr Susanna Malkhasian, UR Vistahermosa: Both are crucial. We can have a good-quality embryo with PGT-A testing, ensuring its health. However, if the endometrium isn’t adequately prepared—whether it’s not thick enough or has other issues—we’ll face implantation problems. The same applies in reverse: even with a perfectly prepared endometrium, if the embryo isn’t of good quality, the transfer won’t be successful. In specific cases, though, we generally prefer to have a good-quality embryo because we have various strategies to improve the endometrium, but none to enhance embryo quality. So, if the embryos aren’t of good quality, the only solution might be egg donation. Within our means, we have many medications and strategies to enhance the endometrium, offering more options to improve that aspect.  

On average, how do you rate the importance of the embryo compared to the endometrium for the average patient?

Dr Evangelos Papanikolaou, Assisting Nature: We should not allow the patients to believe that we have a magical bullet to identify which is the correct time for implantation. So we know from studies after pre-implantation genetic testing, even with donor eggs, that the maximum we can achieve in implantation is around 70%. So in my experience, there are still 30% of patients with obviously at least chromosomally tested embryos that do not implant in almost perfect endometria, or we think that we have prepared them in the right way. I think that if, 70%, is the embryo important and 30% is the proper endometrium. I’m not contrary only in the implantation window but also in how intact is the uterine cavity if the uterine cavity has been modified from previous surgeries, etc. Furthermore, I think that 70% is an embryo and 30% is endometrium, and also immune factors and other factors that take place during implantation, and endocrinological factors.

Dr Halyna Strelko, IVMED Fertility Center: If I can add, there is a guideline of repeated implantation failure, a quite recent guideline, and it was written that if we have a genetically tested embryo, a good quality embryo after 1 unsuccessful embryo transfer, we can think about implantation failure. And in this case, we can think about some additional investigations. If we had non-genetically tested embryos, the probability of implantation would be around 40% because of genetic problems and so on. So in this case, after 2 unsuccessful transfers of good-quality embryos, we can think about additional evaluation.

How thick should the endometrium be? My endometrium is 8 millimeters, and everyone says that’s fine. 

Dr Susanna Malkhasian, UR Vistahermosa: Yes, for 8 mm, it’s a perfect thickness of the endometrium. In our clinic, we use the numbers from 7 to 12 mm of the endometrial thickness that we consider okay for embryo transfer. But we have a lot of patients that, in their cases, never get this endometrial thickness, even when we use the higher doses of hormones and other additional medications. For them, they never get to this thickness, and they may have only 5 or 6 mm of endometrium. Not a long time ago, we started to use some new treatments with platelet-rich plasma, and we saw that even with this kind of endometrium like 6 mm, we can do the transfer, and this woman can get pregnant with this endometrium too. So it’s very important to explain to patients that sometimes we cannot get this perfect gold standard number, and it can be okay too.

Dr Evangelos Papanikolaou, Assisting Nature: There is a huge study, more than 10,000 acceptors, and I don’t remember if it’s coming from Spain or from the United States. It’s a huge registry where they have shown in acceptors with egg-donated embryos that above 7 mm, the result is the same; the clinical pregnancy rate is excellent. So with 6 mm, we have a 10% decrease in the pregnancy rate, with 5 mm, we have a 20% decrease in the pregnancy rate, and less than 5, then the pregnancy rate becomes extremely low. Still, there exist cases that become pregnant, but it is around 10 to 15%. So it seems from this analysis, it’s not a meta-analysis; it’s a retrospective study of a huge data; seems that 7 mm is an excellent threshold. So, patients will not get frustrated if they have 8 or 7. something, and even with 6 mm, we can cancel the cycle, for example. And if we repeat a new cycle, and we see, or we have a registry from the previous treatments that this is approximately the maximum thickness of the endometrium, then we should realize that this 6.2 is the maximum for this particular patient, and we should not frustrate her more than that.

Dr Halyna Strelko, IVMED Fertility Center: It is also important not to have a very thick endometrium because, in the same study, it was written that more than 13 or 14 mm, the chances of implantation also decrease, probably because of bad blood circulation. Optimal thickness indeed is around 7, 8, 9, but more is also not good.

What other testing is recommended for several failures when the endomtrium is good and embryos tested?

Dr Susanna Malkhasian, UR Vistahermosa: One of the first things that we recommend to our patients in these cases with implantation failures is to do the hysteroscopy test because sometimes we can have any problem in the endometrium that we cannot see in the ultrasound, like little polyps or a septum or something like that. So we usually do this diagnosis with hysteroscopy, which means that we have to see the uterus from the inside with a little camera, and it’s very easy to do. So at the same time, if we can see that there is any structural problem, we can fix it. We use it sometimes to have a biopsy of the endometrium to see if there are any endometrial chronic infections or something with different bacteria that can be in this area that could need some treatment. This would be the third thing that we would recommend. Another thing would be to see if there is some other kind of systemic disease. We usually test for autoimmune system diseases. It’s just a blood test to see if we have any other problem that could be fixed with some kind of medication added to the protocol. When we have all these tests and as Halyna said before, the endometrium test to see the genetic expression of the gene and the implantation window, it could be performed too. And if every test is okay, and we still don’t know what’s the reason for these implantation failures, we usually use an empiric treatment with different medication that we have just to try to improve the vascularization of this endometrium, like, for example, heparin, aspirin, and sometimes corticoids, to see if it could help in this stage of the implantation because there are lots of times that we just don’t know where is the problem, but because we cannot study, we have no methods to know everything. And there are lots of parts of the implantation moment that we still don’t know. So sometimes we use this kind of medication just to see if it helps to have a better result.

How can the endometrial receptivity get better or what things could we do to improve receptivity and the endometrium in general after endometriosis and/or adenomyosis?

Dr Halyna Strelko, IVMED Fertility Center: I would like to add to the previous question by mentioning that one of the problems we should also test for is chronic endometritis. When we have chronic inflammation in the uterus, it may displace the implantation window. Some publications suggest that treating chronic endometritis can change the implantation window after, and this is part of the answer to this question.

If initial tests yield no results, additional tests for chronic endometritis could be considered. If we find something, a specific treatment can significantly enhance the likelihood of implantation. Regarding endometriosis, specific immunohistochemistry tests like BCL-6 can indicate the condition’s severity, potentially affecting implantation probability. Therefore, prior treatment for endometriosis, possibly over six months, might enhance the chance of successful implantation. What other options do we have? Personally, I prefer natural cycle embryo transfers because the endometrium responds better to natural estrogens. Unlike replacement hormonal therapy, which provides only one type of estrogen, natural estrogens stimulate better receptor connections and endometrial induction. Additionally, a natural corpus luteum can release substances that relax the uterus, minimizing endometrial contractions and improving embryo implantation probability. Excluding chronic endometritis is crucial. For endometriosis, options may include hysteroscopy, medication, or opting for a natural cycle approach.

What are your thoughts on microbiome testing, not just for chronic endometritis but for lactobacillus, etc? Is there an alternative to vaginal probiotics, or would you recommend them to increase lactobacillus?

Dr Halyna Strelko, IVMED Fertility Center: It’s also important to have a normal microbiome of the endometrium and a good concentration of normal lactobacteria. From time to time we can offer this test. From Ukraine, it is quite difficult to organize the logistics to send these samples to the laboratory, so we don’t do a lot. Still, sometimes we are doing that, and it’s really important to have a normal microbiome of the endometrium, and it may also improve the probability of implantation.

Dr Evangelos Papanikolaou, Assisting Nature: I have some reservations about the microbiome concept. Although it’s now more affordable, so we offer it to a larger number of patients, my concern is that nearly 90% of patients have abnormal lactobacillus concentrations. Essentially, the majority are abnormal. Even with treatment attempts using antibiotics and local lactobacillus in the vagina (since we can no longer offer it in the EU), only a small minority, around 10-20%, see an improvement in microbe concentration when we retest the microbiome 2 to 3 months later.

Performing additional treatments becomes challenging because we cannot postpone the embryo transfer for another 3 months, give other medication, etc., and ask the patient to pay for a microbiome test once again. Most of these patients have probably moved on to using donor eggs, so they face a 50% chance. So, we still see excellent results after two microbiomes, which are still abnormal. However, I still feel that microbiome should be offered when we fail after PGT-A tested embryos. In that scenario, if we transfer a genetically tested embryo, I think we should not let out of the workup the microbiome status of the endometrium because even if this rare cases of 3% 5% as Dr. Halyna just mentioned from chronic endometritis can be identified, and we can decrease a little bit this status of inflammation, and we usually do this by adding corticosteroid afterward in the treatment in the new treatment, then we might expect better implantation for this patient. So definitely, there is a point for this exam, but I think that we are still in the early stages of an evolving exam that should be more and more elaborated in the future and become more accurate.

Could you please address this question regarding microbiome testing and probiotics in your practice? Specifically, is there an alternative to vaginal probiotics, or would you recommend them to increase lactobacillus?

Dr Susanna Malkhasian, UR Vistahermosa: Certainly. Currently, we only have oral probiotics available in our region. While we hope vaginal probiotics will become available again soon, for now, oral pills are what we use. Additionally, we typically provide our patients with a complex of vitamins that includes lactobacillus in another pill. This approach makes it convenient for patients to start treatment upon receiving the protocol, allowing for its effects to be underway by the time of embryo transfer.

Dr Evangelos Papanikolaou, Assisting Nature: In the beginning, the situation was the same in Greece as it is in Spain and other European countries. Initially, we preferred vaginal probiotics to align with the administration of vaginal progesterone. However, it seems that oral preparations are also effective, as gastroenterologists have long prescribed oral probiotics. While it may take a bit longer for the flora to differentiate in the vagina and uterus with oral administration, the new preparations appear to be effective.

Any thoughts on atosiban IV, a particular compound, intravenous for improving implantation?

Dr Halyna Strelko, IVMED Fertility Center: I don’t use this kind of treatment a lot. I know several articles suggest that it may be helpful. I’ve tried it a couple of times, but I don’t have much experience with it. From my side, I would like to add a couple of words about my microbiome and about what we discussed regarding lactobacillus. It seems that it is important to mention that for women in menopause, for example, it is not only necessary to give probiotics, but also perhaps for some months before the transfer, to restore the hormonal level. I mean, to provide some replacement hormonal therapy and a good level of estrogen because, without a normal hormonal level, the microbiome will not be able to restore to normal.

Women who would like to do egg donation treatment come with very low hormonal levels. In this case, as for me, preparation should be done a couple of months before with some replacement hormonal therapy to restore hormonal levels and the microbiome will be better in this case.

What can you tell us about PRP (Platelet-Rich Plasma) for endometrium?

Dr Evangelos Papanikolaou, Assisting Nature:I had started using PRP on a lady with multiple implantation failures, a British lady who came to us after experiencing multiple implantation failures and with an endometrium measuring less than 6.5 millimeters. She became pregnant only after PRP. So, it was our last resort for her. Unfortunately, that lady had to terminate the pregnancy at 24 weeks because of very premature pre-eclampsia. So, unfortunately, she never had a baby after this successful egg donation following PRP. After that experience, I began using PRP more frequently in cases of thin endometrium, not for recurrent implantation failure, but specifically for thin endometrium. I must note that it’s not always effective. Sometimes, it appears to increase endometrial thickness artificially because you’re infusing something into the uterus, leaving something behind, resulting in a false increase in thickness. However, it seems that perhaps the growth factors in PRP, combined with various preparation methods, may have some positive effects on certain patients. Nevertheless, it’s still considered experimental, and individuals should not rely solely on this method.

Dr Susanna Malkhasian, UR Vistahermosa: I agree with the doctor because we don’t have so many studies about that, so we need to wait a little bit to see if it’s really so good. But in our clinic, we use it a lot in both cases: for implantation failures and when we cannot achieve enough thickness of the endometrium. In both cases, we have really good results, but we still have to study more to confirm that it’s so effective.

Dr Halyna Strelko, IVMED Fertility Center: I also have experience using PRP, but I agree that there are different methods of preparation, and I have not had such a huge success rate after using it. For some women, it improves results, but maybe not for all.

Does sugar consumption affect implantation?

Dr Evangelos Papanikolaou, Assisting Nature: I can say that drinking Coca-Cola Zero doesn’t affect implantation. I don’t know if extreme consumption of sugar, triggering increased production of insulin, might affect implantation. I never read any paper on this.

Dr Susanna Malkhasian, UR Vistahermosa: I think that not only sugar is important nowadays, we know that for everything, not only for implantation, but it’s also very important to have a good diet. So, I think that one of the things that I would say to my patient is to have a consultation with a nutritionist to do the right diet because sometimes, in cases of polycystic syndrome or endometriosis, it could help a lot.

Dr Halyna Strelko, IVMED Fertility Center: It raises the question of diabetes, probably because if your patient has high blood sugar because of consumption or because of diabetes, it may, influence implantation. It’s necessary to do some additional tests to see if she has type II diabetes, or she’s obese because obesity also decreases the probability of implantation by around 30%.

What do you think about introducing hCG into the uterine cavity prior to embryo transfer with the purpose of increasing receptivity?

Dr Halyna Strelko, IVMED Fertility Center: Yes, I know this method. It was approximately first published maybe 4 or 5 years ago, and it was proposed to put 500 units of hCG in the uterus 30 minutes before the embryo transfer, and, yes, we have done that several times. In some cases, it may improve the situation with implantation. We don’t have so many cases to give good statistics, but for some patients, we are doing that. It is easy, and I found it to be helpful. It may modify receptors and improve endometrial maturity, but it’s difficult to say exactly what the mechanism is or how it is working. But it’s true that after two or three unsuccessful transfers, we are using that, and it is working. Okay, and it was first published and presented during ASRM 4 or 5 years ago, and they also gave very good results without a specific explanation of why it may be working.

Dr Evangelos Papanikolaou, Assisting Nature: I think that these are crazy things to experiment with that they have done randomized studies years ago with giving HCG not intrauterine, of course, but intramuscular before the embryo transfer with no impact on the implantation. And definitely, there is a rationale because HCG is mimicking LH activity. So LH is the denominator of the implantation phase. LH is a very important hormone during the implantation window because it enhances the expression of many receptors. But giving maybe this is a very low dose, but we should be very careful because if you give a particular endometrium HCG, you might downregulate the expression of some molecules. You can achieve the opposite result. There used to be a study that was interrupted 10 years ago that they were giving extreme doses of HCG on the day of the transfer and in acceptors, and after a certain level of HCG, the pregnancy rates were very, very low. So they had to stop this randomized study. This was from a center in Greece. It was a randomized study published 15 years ago, so they had to quit the study prematurely because of very poor outcomes, not intrauterine, of course, but we should be very, very careful.

I’m very cautious because we have also experienced failure of EmbryoGlue in the past when I was young, and I went to Brussels 20 years ago, everybody thought that it was a real big thing and there were many studies, but when we came into randomization, we found that there is no positive impact of EmbryoGlue on the outcome.


I’ve had 2 failed embryo transfers. O’m 41. Now, I am using a donor embryo from a 24-year-old, should the embryo be PGT-A tested? 

Dr Susanna Malkhasian, UR Vistahermosa: PGT-A testing is highly valuable in our opinion. We recommend it universally, even for patients utilizing egg donation from young donors. Understanding the genetic profile is crucial. While genetic disease rates are lower in young women, we advise PGT-A testing in all cases. We’ve started to use a non-invasive PGT-A called niPGT-A. This helps identify the healthiest embryo for transfer, in egg donation cycles, we have more than 1 embryo. However, the decision to undergo these tests is up to the couple, it all depends on every case as we also have to think about the economic part.

For women aged 39 or older, we recommend going for invasive PGT-A testing to ensure embryo health. For younger couples expecting multiple embryos, we recommend the non-invasive test (niPGT-A), although it doesn’t provide a diagnosis like the invasive method does, as it shows the rates and the possibilities of the disease. But it’s very useful to see which embryo has more possibility to implant. Therefore, it could be an alternative without the need to touch the embryo, as you don’t need to biopsy the embryo with this new technique.

Dr Halyna Strelko, IVMED Fertility Center: We used to recommend PGT-A for the majority of our patients in the past. However, recently, especially for this particular group, we’ve stopped recommending PGT-A. There are several reasons for this. Firstly, the possibility of genetic issues is relatively low. Secondly, there’s a concern about inconsistency in results. If multiple biopsies are performed, the results might give various results. There might occur abnormal cells in a portion of the trophectoderm, despite the rest being normal. There’s also the possibility of discordance between the trophectoderm and the embryo itself. According to some publications, PGT-A isn’t recommended before the age of 38, except in cases of repeated implantation failure or specific concerns. On the other hand, non-invasive tests offer a compelling alternative. They avoid the need for biopsy and eliminate any potential damage to the embryo, even if it’s minimal. Therefore, in my opinion, for egg donation programs involving young donors, I don’t recommend PGT-A. In the case of a non-invasive test, it may be a good idea to do it for most patients because the risk of damaging the embryo is high.

Dr Evangelos Papanikolaou, Assisting Nature: It’s not allowed in Greece to do PGT-A in the egg donation program. I do not agree with this law, but you need to ask for special permission, which they very rarely give if you want to do PGT-A in an egg donation cycle. On the other hand, once we do, we see that 30% or 40% of the embryos are euploid with all the drawbacks that Halyna just mentioned the trophectoderm and biopsy. Therefore, in this particular patient, I don’t know if it failed with her own eggs or donor eggs, but I would strongly suggest performing PGT-A with donor eggs only when they have 1 full egg donation with more than 3 blastocysts failed in our centre or from another centre. In that particular case, a lady after many implantation failures with her own eggs and again failure with donated egg, then I think that with a new donor, we might look into the chromosomal constitution of these embryos because we might identify a paternal factor, especially with borderline oligozoospermia. We might decide to change the sperm in another donation cycle. For this particular patient, I would suggest non-invasive PGT-A, not the invasive one.

Dr Halyna Strelko, IVMED Fertility Center: We often conduct genetic testing on sperm, particularly in cases of asthenospermia, although not frequently. It’s rare to encounter abnormal genetic results because genetically abnormal sperm cells undergo apoptosis and self-destruct. However, in cases of teratozoospermia, where there are fewer blastocysts and a higher likelihood of genetically abnormal embryos, it may indicate the need for PGT-A in egg donation. Another thing is, when we want to do an endometrial receptivity test, we should be sure that we have genetically normal embryos. Otherwise, we will not know what was the real reason. Fixing one problem may not resolve others.


What do your think about “endometrial scratching” before implantation?

Dr Halyna Strelko, IVMED Fertility Center: This method was described maybe 10 or 15 years ago, and initially, we did it quite frequently. However, personally, I no longer use it as I don’t see many benefits. Personally, I prefer to conduct tests for the implantation window, microbiome, and endometritis. We perform numerous endometritis tests, and in cases of repeated implantation failure, we often identify issues with inflammations. Therefore, I’m not very supportive of this kind of treatment.

Dr Evangelos Papanikolaou, Assisting Nature: The old method of pelvic scratching has been proven not to be effective. However, we recently published a meta-analysis that suggests otherwise. Additionally, our studies, along with others, have shown that during hysteroscopy and fundal incision, there is an increase in implantation rates. This procedure induces inflammation and triggers a healing process in the uterine fundus. Therefore, while traditional scratching methods may not yield results, further research is needed on hysteroscopic scratching of the uterine fundus.

Dr Susanna Malkhasian, UR Vistahermosa: In our clinic, we do perform the procedure, but I believe it’s because it’s a straightforward process that can be applied to all patients, and it’s easy to carry out. So, sometimes when we encounter implantation failure, we suggest it because it may enhance vascularization for the next cycle and other related factors. However, I agree with my colleagues that while some studies suggest its usefulness in certain cases, there isn’t clear evidence across the board.

Are there any specific supplements that can inmprove lining or receptivity?

Dr Susanna Malkhasian, UR Vistahermosa: I would recommend making an appointment with a nutritionist for dietary guidance, especially if there are underlying health conditions. It’s also important to avoid exposure to harmful elements like smoking.

Dr Halyna Strelko, IVMED Fertility Center: Some supplements with L-arginine can relax blood vessels, and improve blood circulation. Some women find them helpful, especially for improving blood circulation in the endometrium.

What’s your indication for using endometrial testing or the receptivity plus or minus microbiome? Does it matter which test you use or are they all the same? 

Dr Evangelos Papanikolaou, Assisting Nature: PGT-A is the best test that is available for all of us, for doctors, physicians, and patients. So, regarding endometrial receptivity testing and the microbiome, maybe it should be offered when a patient is undergoing IVF with own eggs with repeated implantation failure. Not after 1 or 2 blastocysts transferred from a single cycle, but at least 5 or 6 blastocysts from a single IVF stimulation, or from at least 4 blastocysts after 2 different stimulations. Definitely, after 1 failed egg donation, I think that we should offer microbiome or ERA testing.

Dr Susanna Malkhasian, UR Vistahermosa: I think we cannot do all the tests for everyone, and we should prioritize them. It will depend on our clinical suspicions, what could be a problem in every case. As my colleague said before, at the beginning of the conversation, we have to see, we have to look at the percentage of the problems because, in more than 70% of the cases, the problem is the embryo. So, the first thing that we should study and exclude is the embryo problems with the PGT-A test. Then, when we still have implantation problems, we start to do all these tests as we said before ERA test, hysteroscopy, and other tests.

Dr Halyna Strelko, IVMED Fertility Center: In my opinion, ensuring the presence of a normal embryo is paramount for successful implantation. Therefore, for women under 37 or 38 years old with high-quality embryos, routine PGT-A isn’t typically recommended by me. However, I suggest considering it to confirm the quality of embryos, as occasionally, despite good quality, embryos may still be abnormal. If cost isn’t a concern, PGT-A isn’t a bad option, especially if it can be done non-invasively. After 2 or 3 unsuccessful embryo transfers with optimal conditions, including good endometrium thickness, embryo quality, technique, and hormonal levels, I might explore different preparation protocols, such as natural or artificial cycles. If there’s still no success, additional tests focusing on the implantation window and microbiome might be suggested.

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Evangelos Papanikolaou, MD, PhD

Evangelos Papanikolaou, MD, PhD

Evangelos Papanikolaou, MD, PhD, is a Reproductive Medicine Specialist as well as a world-class recognized specialist in fertility treatment. Dr. Papanikolaou is the author of dozens of medical publications and has been at the forefront of several innovations and improvements in IVF treatment and is the main visionary and founder of Assisting Nature IVF Unit. He is ESHRE and EBCOG accredited as a Reproductive Specialist.
Halyna Strelko, MD

Halyna Strelko, MD

Dr Halyna Strelko is the Co-founder & Leading Reproduction Specialist at IVMED Fertility Center, Kiev, Ukraine since 2012. Dr Strelko is a certified member of ESHRE (European Society of Human Reproduction and Embryology) and ASRM (American Society of Reproductive Medicine), UARM (Ukrainian Association of Reproductive Medicine). She had a medical practice in France and medical practice in leading Kyiv’s infertility clinics with over 23 years of experience. She speaks English, French and Italian.
Susanna Malkhasian, MD

Susanna Malkhasian, MD

Dr Susanna Malkhasian is a renowned specialist in Gynaecology and Obstetrics. She currently works as a gynaecologist, and she is an expert in Assisted Reproduction, high-risk pregnancy and laparoscopy. She studied a degree in Medicine and Surgery at the Miguel Hernández University of Elche and later specialized via MIR at the Marina Baixa Hospital. In addition, she completed a Master's Degree in Human Reproduction at Rey Juan Carlos University.
Event Moderator
Professor Alan Thornhill

Professor Alan Thornhill

Professor Alan Thornhill is a fertility expert with over 25 years of experience and more than 100 scientific publications in IVF. Specifically, he’s a clinical scientist (specialising in embryology and genetics). Uniquely, he’s worked in IVF and diagnostic laboratories, research, clinical and business management, and even with the UK’s fertility regulator. Working in US and UK-based IVF clinics and consulting globally, he’s been involved in the IVF journeys of thousands of couples (both professionally and personally). He’s helped and advised patients, friends and strangers with issues including low sperm count, sperm and egg donation, genetic testing, surrogacy, treatment overseas and more. He currently works in the biotech industry, and his personal mission is to provide his unique brand of fertility coaching to people in need of help.
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