Selecting embryos for better success

Ana García Sifre
Embryologist at IVF-Spain, IVF-Spain

Embryo Implantation, Embryo Transfer, IVF laboratory, Success Rates

From this video you will find out:
  • What are the three main parameters guiding the selection of the best embryos for transfer?
  • What is embryo morphokinetics?
  • What do fragmented embryos mean, and why do they fragment?
  • What are the 4 stages of embryonic development?
  • What is the structure of the blastocyst?
  • Can a blastocyst be abnormal?
  • What percentage of Day 5 blastocysts are euploid?

How embryo selection can increase pregnancy rates?

In this webinar, Ana García Sifre, Embryologist at IVF-Spain, Alicante, has talked about selecting and transferring the best embryos to achieve the highest chances of success.

How embryo selection can increase pregnancy rates? - Questions and Answers

Do you have any experience using embryo culture that uses GM-CSF? EmbryoGen/BlastGen are the ones my clinic uses.

We don’t use this kind of media at our clinic. Each clinic uses different protocols in its daily routine. In our clinic in Alicante, for example, and the one that we have here (Manchester), we always access every media that we use, and we validate them, but unfortunately, I don’t have any experience with the ones you’ve mentioned.

In your experience, do you think PGT-A improves pregnancy rates?

Yes, I do. PGT-A gives us relevant information on what kind of embryos we have, if we have aneuploid embryos, and we transfer them, we know that the result is going to be a failure in the pregnancy. If we have this information, we can just select the embryos that we know are going to have more chances to become a positive pregnancy. Every clinic is going to say that, and it’s really important. It also depends on the age, but we always recommend it.

Is embryo fragmentation bad for the success of an embryo?

If the fragmentation rate is high, the embryo is not going to develop to the blastocyst stage, so it’s not going to be a successful embryo, it’s not going to create this successful structure that we want. If the fragmentation rate is not as big, they can manage to form this structure anyway, and they can also result in a positive pregnancy. We have a lot of cases that it has already happened, but the fragmentation rate will affect the quality of the embryos.

Are frozen embryo transfers more successful than fresh embryo transfers?

We have almost the same success rates with frozen embryo transfer and fresh embryo transfer. I would say we have like a 99%  of the viability of when we thaw the embryos, so they have almost the same quality. The success rates are quite similar, at least in our clinic.

Is an embryo frozen on day-3 not better than one frozen on day-5?

Not better, as I said, it can be the same, but it isn’t better to do it on day-3. If we froze the embryos at day-5, this embryo at this stage has much more cells, they are formed by hundreds and hundreds of cells, whereas  day-3 embryos have normally around 8 cells. If we miss one cell in this one cell is that in this process of cryopreservation, it will imply more damage in the day-3 embryo than it will do on day-5. I would always recommend going to day-5 and then freeze the embryos and then do the transfer.

Do you freeze all embryos or only high-grade embryos?

We just freeze or transfer good quality embryos grade A or grade B, we always freeze them. If we don’t think an embryo has any possibilities of becoming a pregnancy, we will not freeze it.

Could picking a good sperm with PICSI improve the embryo result if the egg is not the best one?

If the egg quality is not the best, PICSI is not going to improve the outcome of the treatment. PICSI is going to help when the quality of the sperm is not so good, but if we have an oocyte problem, it’s not going to help. We can choose a better sperm and try our best, but it’s not going to change the quality of the oocyte.

I heard that embryo development stops on the on day-4 day, and that is often caused by sperm quality, is that true?

The male factor starts to appear on day-3, it becomes part of the embryo on day-3. It’s true that at some point if we, for example, see that the embryo has good fertilization, good quality on day-2, good quality on day-3,  but suddenly something stops on day-3, after day-3, therefore, we can suspect that this can be related to the male factor. This isn’t going to be the only option, but yes, it can be related to the male factor, when we see that all the embryos are stopping on day-3 or day-4 of development.

I have heard that a bad looking embryo could result in a healthy baby. What are your thoughts on that?

I have seen it, not just heard about it. I have seen that embryos that don’t look as they are of perfect quality, let’s say we have a 3 BC embryo, which is not the best, but still, they have the instructors that we need, and we have transferred them, and we have babies, and we have pregnancies. That’s why we don’t discard any embryos. The optimal embryo to have will always be a 5 AA, 4AA, but sometimes we also have 5,3 3, 3, 45 BC quality embryos, which led to a positive pregnancy and a healthy baby. 

There are different criteria between labs in what to keep and want to discard when we assess the embryo, but we always try to get all the information that we get from the embryo and keep the ones that we think are viable, even if they are not of the best quality.

Any advice on improving implantation?

If we’re talking about the embryos to improve the implantation, I would recommend doing PGT-A testing, I don’t know if in your previous attempt you have already done it or not, but the implantation failure most of the time is related to abnormal embryos. If we know that the embryos are chromosomally healthy, we can just try to deal with this problem. 

If we’re talking about endometrium and the capacity of the endometrium to the implant, there are a lot of tests that you can always do such as the ERMAP test. This is a more clinical part, and it’s better to get advice from the doctor, but there are some tests that you can do to improve the implantation potential.

We are in a donor cycle with donor sperm. What is the quality of frozen sperm versus fresh?

When we talk about donor sperm, we cannot compare frozen sperm versus fresh sperm just like that because when we freeze the sperm, some sperm cells are going to die during this process, and if in the fresh sample we have 50 million,  in the frozen one we will have 30 possibly. It doesn’t mean that the quality is worse, sometimes if we just check the numbers, it seems that I have this frozen donor sperm, and it says that it has 10 million, don’t worry because the majority of the banks had wonderful criteria to select the donors that they use, and they have to fulfil this, they have to have normal sperm and this is not going to be a problem to use frozen sperm.

If it comes from the partner’s sperm, it’s a little different. If the fresh sperm quantity or quality is limited, we will always recommend using fresh sperm because we cannot lose these in the cryopreservation procedure.

Do good looking embryos mostly mean good quality, meaning healthy embryos?

The euploidy and the morphology are not related. If we have a good quality embryo, a 5AA quality embryo, it doesn’t guarantee that it’s going to be euploid, we have nice embryos that after the PGT-A test results, we see are aneuploid, so this is not easy to relate. When we talk about health conditions, as I said, the only way to access that is by doing PGT-A testing, we cannot check it with the morphology.   

Ana García Sifre

Ana García Sifre

Ana Garcia Sifre graduated in Biochemistry and Biomedical Sciences at the University of Valencia (Spain). She specialized in Human Reproduction at the University and Polytechnic La Fe Hospital of Valencia. After her training in 2018, she joined the IVF-Spain team in Alicante, where she works as Embryologist. She speaks fluent English and Spanish.
Event Moderator
Caroline Kulczycka

Caroline Kulczycka

Caroline Kulczycka is an International Patient Coordinator who has been supporting IVF patients for over 2 years. Always eager to help and provide comprehensive information based on her thorough knowledge and experience whether you are just starting or are in the middle of your IVF journey. She’s a customer care specialist with +10 years of experience, worked also in the tourism industry, and dealt with international customers on a daily basis, including working abroad. When she’s not taking care of her customers and patients, you’ll find her traveling, biking, learning new things, or spending time outdoors.


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