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The importance of the embryology lab in optimizing success rates

Alpesh Doshi
Consultant Embryologist & Founder at IVF London, IVF London

Success Rates

Optimizing succcess rates
From this video you will find out:
  • What is ICSI and when is it recommended?
  • What cases call for IMSI (Intra-cytoplasmic Morphology Selected Sperm Injection)?
  • How embryologists grade embryos?
  • How many embryos to transfer?
  • What is Assisted Hatching and how does it help?
  • The role of calcium activation

How can IVF lab work contribute to improving the success rates?

In this webinar, Alpesh Doshi, Consultant Embryologist & Lab Director at IVF London. Alpesh was talking about various options that are used in the embryology lab that can improve success rates in IVF treatments.

How can IVF lab work contribute to improving the success rates? - Questions and Answers

Is the fertilization rate better when using ICSI compared to IVF even if there is no sperm issue?

The answer is no. If there is no sperm issue, we should try and keep things as natural as possible, and we should just use IVF rather than ICSI. So if the sperm is normal and healthy, I would not advise doing ICSI because the fertilization rates are the same.

What are the chances of women over 42 years old getting pregnant with her own eggs? Is it best to go with donor eggs?

Generally, I would recommend that in women who are over 40, if they have a good ovarian reserve, they should try with their own eggs although, it’s important to understand that at the age of 42, you’re looking at around 8 to 10 % of your eggs being chromosomally or genetically normal.

I would strongly advise that if you are going to be considering treatment with your own eggs, which there is no harm to if you’ve got a good ovarian reserve, you should combine the use of genetic testing on your embryos and if there is a genetically healthy embryo, your chances of getting pregnant with your own eggs could be as high as 70%. Don’t lose focus on the fact that if you do have a genetically healthy embryo, you have a very good chance of getting pregnant. But, of course, if you go through multiple cycles of IVF with genetic testing and there is no genetically normal embryo available, then you may take the call to move to donor eggs.

I see many clinics offering ICSI as standard, is there any advantage to this where sperm analysis is good?

As I said earlier, there is no advantage of doing ICSI if not indicated. ICSI is purely indicated in men with a low sperm count or if there is a history of poor fertilization with conventional IVF. ICSI does not give any superior results if there is no indication. If anything, I want you to understand that ICSI has its own risks because by doing ICSI, we can potentially damage the egg as well as you saw ICSI involves passing a needle into the egg, and not all eggs can sustain that trauma, so if there is no indication to do ICSI and the sperm is normal and healthy, I would suggest stick to the most physiological method, which is conventional IVF.

How important is the defrosting of the embryos and timing of transferring into the lining for good implantation? What is done for optimal success in preparing the lining and, in turn, for a healthy pregnancy and birth?

There are many things I want to kind of answer to this question. It’s quite a heavy question, so to optimize the lining, of course, this is a clinical avenue, but typically, I would suggest that if your periods are regular, then you can just consider having what we call a short protocol. When I say short protocol meaning on the second day of your period, you can start taking some estrogen tablets and after 12 days assessing the lining of the endometrium of the uterus and then if the lining is over 8 millimeters, you can start the progesterone and usually on the 6th day of progesterone, you would have the blastocyst transferred. Adequate cycle monitoring is paramount when it comes to success rates and healthy pregnancy and live birth, but, of course, the lab is also very important because of the skill of the embryologist in defrosting the embryos and transferring the embryos, also is important. Additionally, the skill of your clinician in transferring this embryo into the uterus is also very important.

Can the ICSI procedure destroy the egg?

The answer is yes, it can. Some of the eggs are very fragile, in fact, in women of advanced age, the eggs can be very fragile, so by subjecting them to needles, again, if it’s not needed, it’s probably best avoided. ICSI is only for severe male factor infertility. If there is no reason to do ICSI, it should not be done because it can also have contraindications.

Does the use of micro sorting also check the sperm for any vacuoles? Is the use of this machine better the magnified visual observation only?

Microfluidic sperm sorting is a very new technique, IMSI, which is looking for vacuoles in the sperm, it has been around for many years now, at least 12 years, but microfluidics is much better. In my opinion, I would prefer to use microfluidics because, with the imagery of looking for vacuoles in the sperm, it can be very hit and miss. Hopefully, by using a more robust method of identifying sperm with better DNA, such as microfluidic sorting, it will give a more concrete cohort of sperm that are better in achieving fertilization and better embryonic development.

What is your opinion on Embryoscope technology? Does it increase the chance of a successful pregnancy?

I feel I need to give a very responsible answer to this. A lot of this new technology and what we class as add-ons because all these things cost money and, of course, if patients can avoid these costs then, why not. I always say that the benefits of the Embryoscope are that you do not have to remove the embryos out of the conventional incubator, the embryos are continuously kept in a more physiological environment, and embryos are very, very temperature sensitive. If you take them out, they can essentially face a slight trauma, but most importantly, I feel that is one of the main reasons why I would like to use the Embryoscope.

There are quite a few papers that are now suggesting that the intricate level of information that you get from the Embryoscope can potentially aid in embryologists selecting or deselecting embryos for transfer and if you do have a methodology or an algorithm which helps you deselect embryos for transfer then, of course, it will translate into better success rates. I know, it’s all kind of interdependent, but I would like to think that if the clinic has got good validated algorithms, then they will be seeing a much better outcome from using the Embryoscope.

How many mature eggs are needed for 39 or 40-year-old to get a day-5 blastocyst?

It’s a bit of a difficult one to answer because every 39 or 40-year-old displays a very different output. On average, I would say that to get a blastocyst, I would recommend getting at least 10 eggs, so I think the starting point which is the number of mature eggs needed for a 39 to 40-year-old to get up day-5 blastocyst, I think we should be aiming for about 10 eggs.

Which is the best media for pick up, denudation, and ICSI? Media with HEPES or without HEPES?

I generally prefer using media with HEPES or a buffer if I’m working outside of the gaseous conditions. To a lot of the patients, this may not make sense but in the embryology lab, we either work within a gas environment if the embryos are in an incubator, then there are gases around it, which it absorbs to maintain the PH of the media in which the embryos are growing. The answer to this question is that I generally prefer using media with a physiological buffer such as HEPES when I’m doing ICSI and denudation.

What would you say is the normal ‘packing’ of the embryos when sending it to another clinic?

The embryos are transported in liquid nitrogen, so we have specialized biological couriers that come and pick the embryos and are transported in what we call a dry shipper. The dry shipper has got liquid nitrogen in the periphery, which keeps the embryos in a very chilled and frozen state, so the embryos can be in this interim phase where they’re held at minus 180 to minus 196 degrees centigrade during the journey where they’re being transported from one clinic to the other. It can last for a few days. The dry shippers are made to hold the temperature for around 3 to 4 days, so embryos are also sent between different countries nowadays, which can take 24-48 hours to reach the destination sometimes. This is safe, the pregnancies are reported, healthy babies are born, nowadays moving embryos from clinic to clinic is a very common phenomenon.

How are the embryos packed in the dry shipper I’m asking because my clinic did not put protection caps on, and they got lost in the cryo shipper, and we used that 21-day dry shipper, and the receiving clinic was shocked as to how they were packed.

That sounds very radical. They should be packed in a very secure manner, of course, every clinic does it differently, but we use specialized canes in which the straws sit so that it’s easy to retrieve them at the other end. Various clinics use different ways, but it’s basic common sense that embryologists in every clinic should be using very robust techniques to make sure that the integrity of the embryos is maintained. They have to use the right techniques to package the embryos.

What is the survival rate of frozen eggs? Does it vary with age?

Usually, the survival rate of frozen eggs is around 86 to 90%, and the answer is yes, the survival rate does go down with age. Typically, in women over 40, the survival rate can be as low as 70%.

Can assisted hatching happen at any stage of a blastocyst?

Assisted hatching is usually carried out on day-3 of embryonic development, but yes, there is no reason why it cannot be done on day-2 or day-4 or even day-5, it depends on the protocols used in individual laboratories, but yes, in theory, the whole idea is to make a small opening in the shell of the embryo so that the embryo has an escape route to the implant.

What is the state/success rate of Oocyte in vitro maturation?

In vitro maturation (IVM) is not a very advanced technology in its current state. Most clinics are not offering in vitro maturation at this point because the success rates are quite low. We as a clinic do not offer in vitro maturation, of course, it’s got very limited benefit in patients with polycystic ovaries that’s the only patient population that it can assist with. However, you would only do in vitro maturation because you’re trying to prevent any ovarian hyperstimulation from these patients but nowadays, with the better stimulation regimes, mild stimulation there’s hardly an event of ovarian hyperstimulation, and hence in vitro maturation is something which is not utilized, in clinical practice.

Is there an age limit for treatment in your clinic?

Yes, there is an age limit, we have gone up to 45 with treating patients with their own eggs. It’s not to say that if we get a 46-year-old, we will not consider them. The most important thing is not necessarily the age, the most important thing is the ovarian reserve, so even if the patient is 46, but if they have a good ovarian reserve, we will potentially consider offering them treatment.

What are the chances that things go wrong in pregnancy with PGD24 tested proven donor into a good surrogate mother who’s had her children already? Is there an ideal time one should wait and any minimum and maximum years between the births of her children?

I don’t believe that there is any data that says that, but I would say that it just makes logical sense that whilst the surrogate has had her child and if she’s breastfeeding, then, of course, planning another pregnancy is not on the agenda. I would give it a year after the baby is born provided she stopped breastfeeding for at least 6 months before she embarks onto treatment for being a surrogate.

It’s important to understand that PGD tested embryos for all the chromosomes doesn’t necessarily mean that there is a 100% implantation rate, so one of the things that can go wrong is that the embryo may simply not implant. There is a 70% chance that these embryos will implant, but not 100%, so you’ve got a 30% odds that the cycle may not work, the embryo may not implant.

At which stage, you perform the assisted hatching? Do you do a complete hole in the zona or just a partial hole with an intact internal layer in the zona, as you showed in one of your slides?

Yes, I make a complete opening when I do assisted hatching. I make a channel opening that breaches the zona. I do not like zona thinning or anything like that, I just make a complete opening, and I do it on day-3.

Can we trust PGT-A in 100%? I mean there are no mistakes? What is the possibility to destroy an embryo during the biopsy?

No procedure gives you 100%. PGT-A has a 97% accuracy, I believe, so there is still a margin of error. The results that you get are as accurate as technology has made it out to be at the moment. There are still kind of pitfalls when it comes to any kind of technology, and one of the limitations that we have with genetic testing is that there’s something called mosaicism whereby some embryos may have a mixture of normal and abnormal cells and when embryos are mosaic, their true implantation potential is a bit unknown. It then depends on the level of mosaicism they have, so, unfortunately, nothing is 100%, errors can happen in a biopsy, an error can happen in the lab that does the genetic testing, etc. There are very robust protocols in place, double witnessing in place to make sure errors, don’t happen.

When it comes to the risk of destroying an embryo, it’s all about skill, it is an invasive procedure as you saw in the video as well, we’re slicing off some cells of the embryo, so it is an invasive procedure and if the skill is there, then the embryo, doesn’t feel the trauma, but if the skill is not there, then yes, the embryologist can damage the embryo.

I see many comments/claims about labs being very good or not, how is it possible to tell? What should I be looking for or asking? Is it mainly down to the skill of the embryologists or other factors that can create such a difference?

I think ultimately, the proof is always in the pudding. I don’t think many labs would potentially allow you to see the labs, they may do, but it’s also asking the right. Ultimately, it would be reflected in their success rates, so it doesn’t matter how they do things, but as long as the success rates are good in your age group when you have done some comparisons, you will automatically know which clinics run a sound level of practice. That is very important because it doesn’t matter how they do it, as long as they get the success rates. That’s the most important thing, and you will know for a fact once you start looking at success rates of different clinics in your age group to understand which clinics are a bit more superior, even in their practices.

In the cases of the dense and thick zona, do you recommend, assisted hatching before freezing? Partial or complete hatching?

I generally prefer doing assisted hatching when I thaw the embryos, so I would not do the assisted hatching before freezing. I would do the assisted hatching on thawing, complete hatching, so not partial.

How and why does a high BMI impact egg quality, and does unexplained infertility exist? Surely there must be a problem otherwise, the couple (without issues) would conceive?

You’re right. I mean, unexplained infertility is a simple way of everyone putting their hands up and saying we haven’t found a reason. There’s only so much you can investigate a couple, and fortunately, treatment nowadays supersedes the level of investigations you do because ultimately, investigations cost money too. You’re right in thinking that there isn’t anything like unexplained infertility. It’s simply the clinic’s way of saying, well we haven’t found a reason, so let’s label it unexplained infertility. If you keep on digging more and more, you will get to the bottom of what that unexplained infertility is, and it’s no longer unexplained.

In regards to BMI and if it impacts the egg quality, so yes, BMI can potentially impact pregnancy rates and potentially increase miscarriage rates. It can also affect egg quality because, with higher weight, the level of the hormone could be compromised, and these women may need much higher doses of gonadotropins or hormones to stimulate their ovaries.

When using a sperm donor, is an MOT of 10+ ok or does having a higher number make a big difference?

No, MOT 10 is fine, you don’t have to go for an MOT 20. MOT 10 is fine, for IVF.

How long does defrosting of an embryo take?

The defrosting of an embryo takes around 20 minutes, but after defrosting, you have to leave it for about 2 hours in culture media before transferring the embryo, so all in all, in terms of clinical practice, it’s about a 2 and a half-hour process whereby it takes 20 minutes to defrost and then around 2 hours to keep in your incubator before that embryo is transferred back into the uterus.

I am considering to take a frozen embryo by a slow freezing method. What chances does such an embryo have to survive the thawing? If it survives, does it have less potential to implant?

A slow frozen embryo has got a lower survival chance than a vitrified embryo, we know that, so typically, the statistics are that with slow freezing around 80% of the embryos survive depending on the stage at which it’s frozen, and with vitrification 98% of the embryos generally survive. Yes, you do have a bit of a difference there in terms of survival rates, and again, the pregnancy rates can also be lower with slow frozen embryos compared to vitrified embryos.

What do you think about egg banking for older women?

The quality of the eggs is going to be the quality of the eggs when they are frozen. To answer that question, yes, egg freezing can be done at any age in theory, and the sooner you do it, the better. If the concern is that you want to use it for fertility preservation. If you are 40, you’re better off freezing eggs when you’re 40 rather than you’re 42, however, it would be better to consider freezing when you’re 35 rather than 40. The quality of the eggs is going to be the quality at the time of freezing. What’s important to understand is that if you do freeze your eggs when you are 30 or 35, your chances of getting pregnant with those eggs at the age of 40 is going to be much higher compared to your eggs at 40 years of age.

Can you give us good examples of the success rates when considering clinics for those in the 42+ group?

When you are looking at clinics, it’s important to ask them what their success rates are for patients in your age group. Please, do not look at the overall success rates of the clinic because comparing the age group of 35 to 38 is almost pointless. I’ve known clinics that have a very high success rate in older women, simply because they have a much-tailored stimulation regime, such as mild stimulation. I mean, for example, in IVF London, we treat a lot of women with a mild stimulation, our average age is 39 meaning we get a lot of older women as well come through and we see phenomenal success rates in older women simply because we combine mild stimulation with genetic screening of embryos, which gives us a much higher success rate. The answer is that look at your specific age group when you’re comparing statistics between clinics.

What is a mild simulation?

Mild stimulation is when you’re not using the conventional high doses, so typically, the doses of stimulation can be anything from 150 units to 450 units, and at IVF London, we generally use mass stimulation, which is 150 to 225 units. We generally, do not increase the dose more than two to five, which in our experience gives us better quality eggs.

I have not looked a lot into assisted hatching so much, and I understood that hatching happens after the blastocyst stage. I had a good quality untested day-5 embryo transfer that did not implant, I appreciate there could have been many reasons for this although, wondering if assisted hatching could have helped, and would you suggest this for further treatment?

Assisted hatching, even from our regulators, it’s considered to be what we call an add-on, which means that there is limited evidence to prove its benefit. Clinics, if they use it, they either use it because they get good results from it, but it’s important to understand that it’s not a proven technology when it comes to improving success outcomes. I feel that if you have had a blastocyst transfer with a failed implantation, which didn’t result in a pregnancy, and if that wasn’t hatched, then what I would do is in the next cycle, I would certainly, consider assisted hatching. Again, this is individual to the clinic, they may not even have it in their protocols. To do assisted hatching, they may say that there is no evidence for it, so it depends on their belief and their ethos of applying these techniques. Certainly, what I do in my lab is if a patient has had a failed IVF cycle with a good quality embryo, I would consider assisted hatching in the following cycle.

For how long can a frozen embryo be saved? 10 years or more?

In theory, a frozen embryo can be stored indefinitely. The law in the UK allows patients to freeze embryos for 10 years, and if there are any compelling reasons whereby the couple or the individual can lose their fertility, then the law may allow for a further extension on those embryos. By law, it’s ten years at the outset, and if there are any compelling reasons to extend storage, then you may be allowed to extend for another time.

What’s your advice if we have the result that most embryos that have been genetically tested have abnormalities?

We would not consider them for transfer at all. If the embryos are mosaic, meaning that there are some normal cells and abnormal cells, then we need to look at these embryos a bit further. What are the mosaic chromosomes affected and whether it’s safe enough to do a transfer, but of course, whenever you are going to be considering transferring a mosaic embryo back into the patient, the patient needs to have genetics counseling, and the clinic needs to be having very robust protocols to ensure that they have covered all the possible scenarios because it is an added layer of risk.

How many embryos are needed for a 39,5-years-old woman?

We don’t have specific algorithms for a 35-year-old and a 39-year-old. Generally, as I said, to get a good outcome, a clinic would say you would need to have at least 10 eggs, so some women don’t have the ovarian reserve to be making 10 eggs after even one stimulation. These women may have to consider batching off embryos in order, so they may have to go through multiple cycles of IVF to collect the right number of embryos. My answer would be, let’s aim for at least 10 eggs.

When you mention that low stims allow for better egg quality, can I take from this that the medication can damage the eggs?

The medication which is the hormones that we give you is very unphysiological doses. In your body, the doses are very small, when eggs are made, so when we give you very unconventional doses, such as very high stimulation that does have an impact on the quality of the eggs. A lot of recent literature has shown that very high stimulations can be damaging egg and embryo quality. In my opinion, the answer is yes, very high doses of medications can be damaging.

Alpesh Doshi

Alpesh Doshi

Alpesh Doshi is a consultant Clinical Embryologist and a co-founder of IVF London. He is also a co-founder and director of the Embryology and PGD Academy. Alpesh previously worked at the Centre for Reproductive and Genetic Health in the leading capacity as a Director of Embryology for 19 years and was pivotal in optimising the success rates. He was also an honorary consultant at the Reproductive Medicine Unit at UCLH NHS Trust. He holds a postgraduate degree in Human Reproductive Medicine and has qualified from the prestigious Imperial College School of Medicine. Alpesh is a Diplomate of the Royal College of Pathologists and also an ESHRE certified Senior Embryologist. He has been an executive committee member of several international embryology societies and holds a very active interest in promoting education platforms through these professional bodies. He was among the first scientists to bring the egg and embryo freezing technology of ‘vitrification’ to the UK in 2007. He is a world-renowned expert in the biopsy of human embryos for genetic testing. Alpesh has authored several papers in high impact journals and written several book chapters in addition to being an honorary lecturer at University College London where he teaches embryology on two of the Master’s courses. He has been an invited speaker in many international conferences and workshops as well as several Health chat shows on television including Zee TV and ITV’s This morning. Alpesh has a special interest in fertility preservation, preimplantation genetic diagnosis and genome editing of embryos.
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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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