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.
During his presentation, Alpesh Doshi talked about the importance of the embryology laboratory in optimizing success rates. Alpesh emphasized that is it very important to understand that there are clinical success rates, so your clinicians are very important, at the same time, you want to make sure that the embryology laboratory is also generating very optimum success rates. It is always the clinician or the doctor and the embryologist together that give the outcome of a success rate in an IVF clinic.
One of the main areas of optimizing patient outcomes is individualizing their treatment journey or patient care. It’s crucial not to treat patients as a one-size-fits-all because every patient is very different. One of the ways it’s done is by carefully monitoring the development of the embryo and selecting the right embryo for that patient. Embryo selection is very patient-centric, the embryos are looked at very individually based on the couple and the patient and then are selected for transfer. The precise monitoring of embryo development is also very significant to have a very fine-tuned approach to embryo selection.
In Vitro Fertilization (IVF)
IVF is one of the primary procedures that is offered for couples experiencing infertility in most fertility clinics. There are several stages of IVF treatment. The first stage is ovarian stimulation with hormones or medications and expecting multiple follicles to grow in the ovaries. During this follicular or ovarian stimulation, the patient has regular ultrasound scans to make sure that their follicles are growing as expected. Once the follicles have reached a certain size and are showing maturity, the eggs will be retrieved by a procedure called egg collection.
The procedure is very straightforward, it takes about 30 minutes, the patient is sedated, a needle is passed through the vaginal wall, and the follicle or all the follicles are aspirated. On the same morning of the egg collection, the sperm is also prepared, so the male partner produces a sperm sample, and the sperm will be prepared in the laboratory to clean the sperm and make it ready for fertilization. On the same afternoon, the sperm is inseminated with the eggs either by conventional IVF, if the sperm is of good quality, or sometimes we have to use ICSI (Intracytoplasmic Sperm Injection), whereby the sperm parameters are quite poor. Whether you do IVF or ICSI, that is purely based on the sperm parameters, once the eggs are inseminated, and have fertilized, then the journey involves continuous monitoring of those developing embryos and ultimately, after 3 to 5 days of embryonic development, we would then transfer 1 of these embryos back into the uterus and freeze the remaining embryos if they’ve developed further.
ICSI (Intracytoplasmic Sperm Injection)
ICSI is the method to inseminate the eggs in cases of severe male factor infertility. If sperm counts are less than 10 million sometimes, then it might be better to use ICSI as the procedure. The initial stage of any decision-making when it comes to the sperm and the method of insemination is to do a semen analysis. Once the semen analysis is done, the count, motility, and morphology of the sperm are assessed, and it is then decided whether to use conventional IVF as the method of fertilization or ICSI.
In some men, the count of sperm could be very low, less than 1 million, which means ICSI is the only option. In very few men, we could potentially find no sperm in the ejaculate. That means they may need a bit more of a urological assessment by a consultant urologist to see whether they have any blockage in their reproductive tract, which is preventing the sperm from coming out. If there is some form of blockage, or sometimes there is no blockage and yet no sperm, the urologist may consider doing an invasive procedure like a testicular biopsy. A small biopsy is taken from the testicle, and the sperm are retrieved from the testicle directly and used in ICSI.
IMSI (Intracytoplasmic Morphologically Selective Sperm Injection)
In cases of repeated miscarriage or high sperm DNA fragmentation, which can potentially result in a higher miscarriage rate, one of the treatment options that is recommended is called IMSI, which stands for Intracytoplasmic Morphologically Selective Sperm Injection.
It’s like ICSI, but the sperm is magnified to almost 1000 to 6000 times to see the level of detail in the sperm head, which can essentially give a much clearer picture of the health of the sperm. When embryologists magnify sperm to that degree, they may be able to pick sperm which are much healthy and have a much higher implantation potential.
Embryo grading & embryo transfer
On day 0, we’ve got the egg, and on day 1, about 18 hours after insemination, there is normal fertilization, on day 2, another 24 hours later, the embryo should be between 2 and 4 cells or 2 and 5 cells, on day 3, about 72 hours after insemination the embryo should be between 6 and 10 cells in development and by day 5, which is five days after egg collection, the embryo should be at the blastocyst stage which is an embryo with over 150 cells. It is at this stage, ideally, that it’s best to do the embryo transfer. Embryo transfers can be done on day 3 or day 5, however, by pushing embryos transfers to blastocysts, we give the patients a much higher chance of getting pregnant because we know that nature has its funnels in terms of which embryos are going to make it to the blastocyst and which ones aren’t.
We may have 5 day-3 embryos, but we would potentially only expect 2 of those embryos to make it to blastocyst. Why do an embryo transfer on day 3 not needed? It’s simply because if you have a choice of embryos, you might as well pick the best embryo because with embryos, it’s all about the survival of the fittest theory embryos are going to go through this funnel, and you will start with a higher number of eggs you will potentially have 70 or 80% of those eggs fertilized you would potentially have about 60% of them make it to day 3, and potentially about 40 to 45% of those embryos to make it to day-5. It makes absolute sense to delay the embryo transfer to the blastocyst stage to give you the best chance of pregnancy. However, some clinics do a day 3 transfer because it helps them plan their weekend work. You can imagine that if someone’s had an egg collection on a Tuesday, this means that if they do a day 5 transfer, then the embryo transfer will be on a Sunday, which the clinic may not like doing because it needs to get all the staff in. They may just do an embryo transfer on a Friday, which is day 3, we all know that this is not necessarily giving the patient the best chance of pregnancy, especially if the patient has got multiple good-quality embryos available on day 3, it makes absolute sense to wait to the blastocyst stage and select the best embryo for transfer because in that way you have weeded out the embryos that are not distinct to make it.
The number of embryos to transfer
Transferring multiple embryos adds another layer of risk when it comes to multiple pregnancies and outcomes of a healthy baby. Therefore, in the UK, there are very strict guidelines in terms of when to transfer more than 1 embryo, and in most European countries, nowadays, single embryo transfer is the norm. In the UK, generally, only 2 embryos are transferred if the patients are over 40. There are risks associated with multiple pregnancies, there is a higher risk of miscarriage, premature delivery, etc.
- guidelines recommend an elective single embryo transfer
- reduces multiple pregnancies
- the risk associated with multiple pregnancies
- maternal complications
- neonatal death
- long-term health problems with the child
- double embryo transfer only slightly increases pregnancy rates
If you have multiple blastocysts available, the rest of the embryos are frozen.
- vitrification means quick freezing of embryo and storage in liquid nitrogen
- 98% embryo survival rate after vitrification and warming
- same pregnancy rates achieved with frozen embryos as fresh
- frozen cycles are more popular as the levels of hormones are lower, and the patient is less at risk of OHSS
Assisted hatching is an innovation that is making a small opening in the shell of the embryo with a laser beam to help blastocyst hatching to take place. It’s a rather safe procedure, mostly, assisted hatching benefits women over the age of 40 because there’s some level of indication that such women have a much harder shell around the embryos, so assisted hatching can give a much better chance of these embryos implanting. It can also be beneficial in women with a higher FSH level of more than 9 IU and patients with previous failed cycles despite having good quality embryos.
Another procedure called egg activation using calcium ionophore may be effective at improving fertilisation rates in ICSI cycles. By using a certain culture media such as a calcium ionophore it’s possible to increase the level of intracellular calcium so that the sperm starts doing its function and the egg realizes that it needs to start the events of fertilization. Typically, it’s used in patients with a poor fertilisation rate of 30% or lower. In some studies, it’s been seen that using calcium ionophore in patients with poor blastocyst quality or development also helps and has given a much better outcome not only in terms of the number of blastocysts but also the quality of the blastocyst.
The next thing discussed by Alpesh Doshi was sperm preparation. The traditional methods of preparing sperm in a laboratory include using a centrifuge, and to spin the sample down. However, research has shown that when you turn the sample down, you can essentially induce some damage to the sperm. There is a new method of sperm preparation called Zymot, or Microfluidic technology, and this technique is mainly aimed at men who have got high sperm DNA fragmentation. The idea is that the sperm are going to be passing through very narrow microfluidic channels so that the sperm that reached the other side is the healthiest, although the numbers will be much lower, but for ICSI whereby you need only a handful of sperm. It is worthwhile applying this technique to get the healthiest sperm on the other side, which can potentially be a game-changer for many patients going through IVF.
The data on Zymote shows that DNA fragmentation is much lower compared to other methods like density gradient, centrifugation or just a routine swim-up. The fertilization rate with Zymox sperm is much better, and also the number of genetically healthy embryos is much higher compared to density gradient or using a centrifuge.
One of the other advances in clinical embryology is the development of the Embryoscope. The Embryoscope is an incubator that has got a camera in there, and whilst the embryos are incubating in a very physiological environment without them being taken in and out of the incubator to observe under the microscope. The camera is capturing all the information needed to capture. Usually, images are taken every 15 to 20 minutes of the embryos as they develop. The number of images recorded is played in the form of a video when the embryologists are ready to be selecting the embryos for transfer. They will be playing these videos and comparing the embryos. Based on how the embryos are developing, the embryologist uses very specific algorithms or sometimes even artificial intelligence algorithms so that they can select the best embryo for transfer.
One of the major applications in the laboratory nowadays in most IVF units is the application of genetics. One of the reasons why embryos do not implant or result in a miscarriage is because the embryos have genetic abnormalities. There is the technology of Pre-implantation Genetic Testing for aneuploidies (PGT-A), previously called PGS, which enables us to see what’s happening with the embryo at the genetic level. 90% of the embryos that fail to implant or the embryos that result in a miscarriage are genetically or chromosomally abnormal. Therefore, PGT-A gives information on which embryos are normal and healthy and which are genetically abnormal. To do that, a small biopsy is required. Some cells from the embryo are put away, and the idea of genetic testing is that when you get the report, it will tell you which embryos are genetically healthy and which have got aneuploidies. After that, only genetically healthy embryos are selected and transferred, which potentially gives a higher pregnancy rate to the couple and lowers the miscarriage rate as well. After the biopsy is done, the embryos have to be frozen as they cannot be transferred fresh, the genetic results take about a week to 10 days. Once the results are obtained, it’s possible to plan an embryo transfer with the patients.
Apart from conventional PGT-A, it’s also possible to do genetic testing for known genetic conditions such as cystic fibrosis, breast cancer, Thalassemia, Muscular Dystrophy, Retinoblastoma, etc. It’s called PGT-M (Preimplantation Genetic Testing for Monogenic disorders). Many different types of genetic disorders can affect couples and pose a higher risk of them transmitting that genetic abnormality to their children, so for these couples, although they may not be infertile, there are options to have genetic testing of their embryos done to select the normal embryos from the abnormal embryos especially if they’re carrying a genetic disorder.