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Blue quadrant showing 4 different embryos at different development stages

16/01/2024 - 7 min read

How we select your best embryos with Caremaps-AI®

Care Team

As has been done for decades in the field of IVF, we grade each and every embryo in the lab by its appearance (known as the morphological grade).

We are delighted that at Care we can enhance our embryo grading using Caremaps-AI®; a clever, new technology that also grades your embryos based on their development throughout their week of culture, and not just their appearance. This ultimately enables us to better select the embryo that is going to give you the best chance of having a baby. This blog describes how we grade and select your embryos in the lab and the benefits of having Caremaps-AI® on your treatment plan.

Care’s morphological embryo grading system

5 days after your egg collection the embryo should have reached the blastocyst stage, at which point it will have around 150 cells and will be filled with fluid. A blastocyst is considered the strongest stage of an embryo, it is the highest potential that we are able to observe in the laboratory that the embryo is capable of forming a pregnancy. At this point, we can grade the embryo on its appearance. This is known as a morphological grade. We look at:

  • the expansion status of the embryo – i.e. how ‘big’ the blastocyst is - this can vary from a very early blastocyst (VEB), early blastocyst (EB), full blastocyst (FB), expanded blastocyst (ExB), hatching blastocyst (HB), or fully hatched blastocyst (FHB)
  • the inner cell mass of the embryo (the part that forms the baby)
  • and the trophectoderm of the embryo (the part that forms the placenta)

We classify anything with grades 1 or 2 as good quality (and suitable for freezing), and anything with grade 3 as borderline/poor quality. Embryos with either the inner cell mass or trophectoderm graded as a 3 can be frozen if we consider them to be borderline, and the other cell type is good quality, but the survival rate of these embryos may not be as high as a good quality embryo. We don’t freeze anything that scores a 3 for both cell types.

Without time-lapse

When embryos are cultured in standard incubators, they are left undisturbed for their 5 days of culture (except for when checking them for fertilisation). In order to assess the grade of each embryo on day 5, we have to remove your dish from the incubator and have a very quick look under the microscope at each embryo. This means that we only have a brief snapshot of how the embryo looks before we make the decision about whether to transfer, freeze, or discard each embryo.

With time-lapse and Caremaps-AI®

If your embryos are cultured in our time-lapse incubator, this means that photos are automatically taken of your embryos every ten minutes throughout the 5 days of culture. This gives us a time-lapse video of your developing embryos to analyse, and therefore much more information than just the embryo’s morphological grade (as described above). For example, we can see how long the embryo took to reach 2 cells, 4 cells, 8 cells, and so on. We can then use AI software to analyse this information and apply a specific morphokinetic algorithm (known as Caremaps), which scores embryos on their live birth potential from 1-10 (with 10 being the best) based on how closely they hit the right milestones at the right timepoints. It is very normal for embryos to look identical, but have very different Caremaps scores.

For example, we may have three embryos that have the exact same morphological grade and we cannot easily distinguish between them on eyesight alone. However, we find they have Caremaps scores of 2, 6, and 10. We know from our extensive research that:

  • Caremaps score 2 has a 7.4% chance of live birth.
  • Caremaps score 6 has a 26.2% chance.
  • Caremaps score 10 has a 45.9%.

 Therefore without the algorithm, we may inadvertently choose an embryo for transfer that has a lower live birth potential than a second available embryo. Of course, this second embryo could be frozen for future use, but our goal is for you to take home a baby as soon as possible and therefore we want to be sure we are choosing the embryo with the highest potential in the first instance.

Using Artificial Intelligence

Once the embryos have been given a morphological grade, the Caremaps algorithm is run on all blastocysts that are deemed suitable for transfer or freezing. The algorithm actually takes into account the final morphological grade, along with the developmental time points mentioned previously. To select the embryo to transfer, we always choose the embryo with the highest Caremaps score. This award-winning algorithm has been created specifically for Care patients and is based on over 6000 embryos. The algorithm is regularly validated against our latest results, ensuring when your embryo is analysed, it is done so by the most up to date technology.

Until recently, studying and annotating the developmental timepoints of embryos in order to generate a Caremaps score was a task completed by the embryologist. Although our embryologists are all very well-trained in studying embryos, we are human and some developmental timepoints have always been relatively subjective. We are really pleased therefore to introduce new artificial intelligence software, Caremaps-AI®, which looks at the development of your embryos automatically – it is very robust and was trained on nearly half a billion photographs of embryos! Using AI means that every embryo is annotated consistently, which makes us even more confident in grading embryos with Caremaps. Furthermore, marking every time-point for each stage of development for each embryo was a very time-consuming process for embryologists. This time can now be used to focus on other important lab processes and of course be on hand to answer any questions you might have.

Implantation rates and Caremaps-AI®

Caremaps-AI® is the most advanced piece of equipment we have in the laboratory to select the best embryo for you- the embryo that will give you the best chance of having a live birth. Although our system is very clever, the scores are still just a prediction. There is still the chance of having a high-quality embryo transferred, with a high Caremaps score, and it sadly still fails to implant. It is very hard for us to understand why this happens. The doctors will do everything to prepare your uterus lining for transfer and the embryologists will do their very best to create and select the best embryos they can for you.

However, there are crucial interactions between the uterus and the embryos that need to occur in the days after the transfer, which we are not able to control or visualise. Studies are ongoing in this area - they are understandably very hard to undertake - but we are hopeful that in the future we will be able to gain a greater understanding into why some embryo transfers are not successful. Another reason may be that some high-grade embryos fail to implant because they are genetically abnormal. The chance of genetic abnormalities occurring in an embryo does usually increase with the age of the egg provider, therefore genetic testing may be recommended to you if deemed appropriate by your doctor.

Please rest assured that lower grade embryos can still be transferred, as they still have a chance of resulting in a live birth. We would not transfer embryos we did not think had a chance of implanting. If an embryo has a lower Caremaps score, as you might assume, it does mean it has a lower chance of resulting in a live birth, but it does not mean there is no chance at all.

How much is Caremaps-AI®?

Caremaps-AI® costs £995 on top of your treatment costs and is available to everyone. However, using Caremaps means that, as the best embryo is selected for you initially, it may reduce your chance of having to return for repeat cycles in the future.