How are the best embryos created and selected for IVF treatment?

Vladimiro Silva, PharmD
Scientific and Executive Director, Ferticentro

Embryo Transfer, IVF laboratory

From this video you will find out:
  • What are the key steps in the IVF process for creating embryos?
  • How is the quality of embryos assessed and determined?
  • How does embryo morphokinetics impact the selection and development of embryos for successful implantation?
  • How is AI currently being used in the selection of the best embryos for IVF, and what are the potential future developments or applications in this field?

How are the best embryos created and selected for IVF treatment?

During this event, Vladimiro Silva, Founder & IVF Lab Director at Ferticentro, Coimbra, Portugal, discussed embryo selection process in IVF treatment, offering invaluable insights and expertise.

The role of female age in egg quality

When we consider the eggs, female age is the most crucial factor. As presented in the graph from the Centers for Disease Control and Prevention (CDC) – a national public health agency of the United States, the probability of a pregnancy declines with female age.  The younger the woman, the better the quality of her eggs. The opposite is also true when comparing cycles using donor eggs, where the eggs are of good quality.

The impact of sperm quality

There were some studies in Denmark claiming evidence of decreasing sperm quality over the past 50 years. However, a study published in the British Medical Journal showed no significant downward trend in sperm quality. Many factors can affect sperm quality, including exposure, lifestyle, toxicants, and alcohol.

For instance, a study from Denmark compared sperm quality in different seasons and locations, showing that sperm quality tends to be better in the winter. This illustrates the need to be cautious when interpreting these statistics. Factors such as exposure, and lifestyle can affect sperm quality.

Sperm takes around 90 days to be produced, and there are fluctuations within the same men throughout the year. It’s crucial to consider various factors that affect sperm quality. Good sperm and good eggs are essential for creating good embryos.

A study in human reproduction found that the egg contribution to embryo quality is about 70 to 80%, while the sperm contribution ranges from 10 to 15%. When the paternal component is abnormal, it can significantly impact embryo development and pregnancy.

Creating the best embryos

There are two main techniques for creating the best embryos. The first is classic IVF, where we stimulate the woman’s ovaries, collect the eggs, fertilize them with sperm, and transfer the resulting embryos to the womb. The second technique, ICSI (Intracytoplasmic Sperm Injection), involves injecting a single sperm directly into the egg. ICSI is the most commonly used IVF technique, and it has greatly improved the success rates of IVF treatments.

Creating the best embryos requires state-of-the-art laboratories, highly trained embryologists, and a commitment to ongoing improvement and quality control in IVF clinics. We need to ensure that we have the best conditions, culture media, and technology to achieve the best results. This systematic and analytical approach allows us to continually refine and enhance our IVF procedures.

Embryo classification in IVF labs

In IVF labs, daily work involves classifying embryos. Several methods exist, one of which is morphological classification, which has been in use for over 20 years. It relies on static images and was used before the advent of incubators with built-in video cameras. Embryos were taken from the incubator, observed under a microscope, and classified based on visible characteristics. For example, embryo ‘A’ with two pronuclei (from both parents) and two polar bodies is considered a good and normal fertilization. Embryo ‘B,’ with three pronuclei, suggesting an abnormal number of chromosomes, may be excluded.

Morphological classification, while historically useful, has limited correlation with genetic viability, especially when evaluated using preimplantation genetic testing (PGT). Therefore, clinics now employ more advanced methods, such as PGT-A, both invasive and noninvasive, as well as artificial intelligence and morphokinetics.

Blastocyst formation and advanced classification

For a deeper understanding, consider the development of blastocysts. On day four, embryos progress to the morula stage, with around 16 compacted cells. On day five, blastocysts begin to form, exhibiting an inner cell mass and a trophectoderm. Well-defined blastocysts with clear areas are considered to have excellent prognosis. On day six, embryos grow so large that they become challenging to observe under a microscope.

Previously, embryos were regularly removed from incubators for observation, exposing them to potential temperature fluctuations, light, and pH changes. To minimize such disruptions, many IVF clinics now employ time-lapse technology, with built-in video cameras within incubators.

While morphological classification remains a part of IVF practices, it’s no longer the sole determinant of embryo selection. Advanced techniques, such as PGT-A, noninvasive methods, and AI, have transformed how embryos are evaluated and chosen for transfer or freezing. IVF labs have shifted from relying solely on morphological classification to incorporate more sophisticated methods that enhance the likelihood of successful implantation and a healthy pregnancy. The field continues to evolve with advances in technology and understanding.

Embryoscope is an incubator equipped with an integrated video camera. This device enables embryologists to cultivate embryos continuously, beginning immediately after sperm insertion into the egg. Using the embryoscope, the embryologists gained valuable insights into the development of embryos. With real-time observation, they can monitor the intricate processes occurring inside the incubator. For example, embryologists observe the development of embryos.

Analyzing embryo development with AI

As we explore the use of artificial intelligence in assisted reproduction, it’s important to discuss the application of AI in embryo assessment and selection. AI holds immense potential in the field of assisted reproduction. While we currently rely more on embryologists than machines, AI’s progress promises to enhance our understanding and selection of embryos. AI can see aspects that the human eye might overlook and analyze embryo development in a systematic and reproducible manner.

Within AI, machine learning and deep learning are crucial. Machine learning assesses fixed embryo images, while deep learning observes the embryo’s evolution through raw images, making it a powerful tool.

Several AI methods, such as EMA and the iDAScore, effectively identify high-quality embryos, simplifying the assessment process and improving consistency and accuracy. Comparing different scoring methods, EMA has shown slight superiority over manual evaluation.

AI in reproductive science is rapidly evolving, offering great promise for embryo selection and improving IVF success rates. While we have not reached complete reliance on machines, AI is becoming an invaluable tool in the field of assisted reproduction, providing us with new ways to select the best embryos.

- Questions and Answers

What is the significance of blastocyst culture in the context of IVF and how does it impact the selection of embryos?

Blastocyst culture involves extending the embryo culture until day 5 or day 6. However, it’s crucial to understand that extending the culture won’t improve the quality of embryos. If an embryo is of poor quality, extended culture won’t change that. Good embryos remain good, and bad embryos remain bad. The value of blastocyst culture lies in providing more information about the embryos. This information helps us make informed decisions, such as whether the embryo is viable for transfer or if it should be frozen or undergo preimplantation genetic testing for aneuploidy (PGT-A).  

I’m 38 and have experienced recurrent miscarriages. How can my previous pregnancy complications be taken into consideration during the creation and selection of embryos?

For patients with recurrent miscarriages, we strongly recommend preimplantation genetic testing for aneuploidy (PGT-A). PGT-A won’t improve embryo quality but allows us to determine if the embryos are viable. When working with such patients, we aim to obtain as many embryos as possible to increase the chances of finding viable embryos. By knowing the embryos’ genetic status, we can differentiate between genetic and non-genetic factors contributing to recurrent miscarriages. This information helps tailor our treatment strategy, focusing on addressing specific issues related to the endometrium or other factors that may be causing the complications.

Are there ongoing research or developments in AI for embryo selection that patients should be aware of as they plan their treatments?

Yes, there are ongoing developments in AI for embryo selection. The field of artificial intelligence is continually evolving. For instance, at a recent conference by the American Society for Reproductive Medicine (ASRM), there were presentations on AI in assisted reproduction. AI is advancing rapidly, and innovations are making their way into clinics. Patients should keep an eye on the latest developments and innovations in AI for embryo selection. AI’s role in embryo selection is likely to grow, and it will help embryologists make more accurate assessments of embryo viability.

Could AI potentially replace embryologists in the future?

The role of embryologists may change significantly due to the use of AI in embryo selection. While AI can provide valuable insights and predictions, it’s unlikely to completely replace embryologists in the short term. AI can assist with analysis, but the hands-on tasks of handling embryos will still require human expertise. The trust in AI will grow over time, and embryologists will likely validate AI-generated conclusions. However, it’s doubtful that AI will completely replace the role of embryologists in the foreseeable future.

How long have you been working with AI for embryo selection in your practice?

We began developing our AI algorithm for embryo selection approximately three years ago. Over the past year, we have been using it routinely in our practice. However, we still rely on traditional methods such as morphological assessment and morphokinetics alongside AI. The final decision regarding embryo selection is made by the embryologist. AI is an evolving field, and we are constantly testing and comparing its results to improve our selection process.
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Vladimiro Silva, PharmD

Vladimiro Silva, PharmD

Vladimiro Silva, PharmD, embryologist, Scientific and Executive Director at Ferticentro and Procriar, two of the leading IVF centres in Portugal. Doctor of Pharmacy, Faculty of Pharmacy, University of Coimbra. MSc in Health Economics, Faculty of Economy, University of Coimbra. Post-graduated in Health Services Management, Faculty of Economy, University of Porto. Post-graduated in Clinical Analysis, Faculty of Pharmacy, University of Porto. Author of hundreds of lectures, oral communications, posters and scientific articles in Portugal and abroad. Vladimiro Silva speaks: English, French, Spanish, Italian and Portuguese.
Event Moderator
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.