What percentage of 3 day embryos get to blastocyst stage? What percentage of embryos make it to day 5 blastocyst? Is the embryo transfer day important? What is the difference between day 3 and day 5 blastocyst transfer? Which option, day 3 or day 5 blastocyst transfer, should you choose
If you have doubts like this, you are in the right place. Watch the video below from the webinar organized by EggDonationFriends and presented by Dr. Carmen Avilés Salas who is a gynecologist specializing in reproduction at the Reproduction Unit of Clínica Vistahermosa in Spain (PreGen). Dr. Avilés is a member of Spanish Society of Gynaecology and Obstetrics (SEGO) and Spanish Society of Fertility (SEF). We had the pleasure to have Dr. Avilés onboard for our webinar project. The webinar contains an in-depth presentation about the difference between 3 day and 5 day embryo transfer from the best professionals in the field.
The embryo transfer day – is it better to transfer embryos on day 3 or day 5 at blastocyst stage?
Deciding whether to have a three or five-day embryo transfer is a widely debated and controversial topic. It’s usually a clinic-led choice, upon which patients are advised, by their embryologists and consultants, as to what would be best in each unique situation. But what is it that drives clinics to recommend one over the other, and what questions should clients be asking when researching this decision?
In this webinar, Dr Carmen Aviles Salas looks at the various reasons and factors as to why a transfer, on a certain day, might be suggested. She shares her insights into whether one is better than the other, and what differences there might be. Dr Aviles Salas is a gynaecologist specialising in reproduction. She is a member of both the Spanish Society of Gynaecology and Obstetrics (SEGO) and the Spanish Society of Fertility (SEF).
IVF is used in order to create a viable embryo, for transfer, under laboratory conditions. Once an egg has undergone fertilisation, either by IVF or ICSI (where one sperm is injected directly into one egg) it is then cultivated, in an incubator, and monitored by the clinic’s embryology team. For an embryo to develop, the sperm needs to fertilise the egg, and the cells, created by this process, need to split and multiply.
In natural conception, a fertilised egg would usually arrive at the uterine cavity at blastocyst (day five) stage, and go on to implant, becoming a pregnancy. As IVF is there to simulate this situation, why therefore, would a three-day transfer even be contemplated, if an embryo wouldn’t naturally arrive, in the uterus, until day five?
Before starting to look at the arguments surrounding three-or-five-day transfers, it’s key to note that, whilst a five-day transfer might replicate the natural workings of the body more closely, three-day transfers can, and do, result in pregnancy.
Not all embryos are equal and various factors are known to affect their condition. Oocyte (egg) quality can be diminished, due to reasons such as age or illness, and issues with sperm, such as DNA fragmentation can also affect the calibre. Each embryo created is unique and will vary in both its development and quality, which is why monitoring embryos is a crucial part of the IVF experience. Clinics will, usually, have a grading system, rating embryos according to their maximum implantation potential. In order to classify each embryo, labs will monitor the progression, daily, garnering important information about each set of cells. This information is then used to determine whether transferring at cleaver (three-day) or blastocyst (five-day) stage is likely to offer the best chance, of conception, in each situation.
After fertilisation has taken place and the embryo has been created, an embryologist would expect the impregnated oocyte to begin its first cleavage division, of becoming two cells, after, approximately, 24 hours. The hope then is that these cells continue doubling, reaching four cells, after circa 48 hours, arriving at eight cells on day three. It’s this day three quality, of each embryo, that Dr Aviles Salas advises is a key determinant for selecting at which stage the transfer should take place.
Alongside cell division, the number of embryos a patient has also plays an integral part in the decision-making process. If a patient only has one or two healthy, eight-cell embryos on day three, then a cleaver stage transfer will, usually, be advised. This would also be the same for patients with lower quality, but viable, embryos, of perhaps six to seven cells, after 72 hours, or with fragmentation issues. It’s currently understood that, for these types of embryos, survival is increased, in utero.
Even though a laboratory will replicate, as closely as possible, the conditions of the uterus, from temperature, to humidity and oxygen levels, lower grade embryos are less likely to survive, to blastocyst stage, in a clinical incubator. Put simply, under these circumstances, transferring an embryo into the uterine cavity, on day three, allows a greater possibility of pregnancy.
However, if a patient has more than three, well graded, equally divided embryos, after 72 hours, then clinics would, most probably, continue cultivating them in an incubator and recommend transferring a blastocyst (five-day embryo). A top-grade embryo would typically have the correct number of cells, at each stage, and be regular in its appearance and shape; symmetrical, with no fragmentation.
Patients, who have repeatedly failed to achieve a pregnancy, following the transfer of good quality cleaved (three-day) embryos, could also be offered the option of a blastocyst stage transfer, as would those requiring genetic analysis; Dr Aviles Salas reports that embryo biopsies cannot take place before day three.
When looking at pregnancy rates, following three and five-day transfers, data, from the Spanish Society of Fertility (SEF) shows that blastocyst stage embryos do result in a higher pregnancy rate. Out of 51.2% of cleaver stage transfers, 37.9% ended with a pregnancy whereas, out of 11.2% blastocyst transfers, 47.3% were recorded as ending with a positive test result. The percentages were both increased with the use of donor eggs.
Whilst it may appear, from these findings, that “blast is best”, Dr Aviles Salas advises that it’s important to note the much lower figure (11.2%) of five-day transfers, when compared to those taking place on day three (51.2%) as recorded by SEF. She advises that blastocysts aren’t transferred as regularly as cleaver stage embryos, and this is due to the reasons, previously discussed, surrounding clinical understanding that, with lower quality, or lower amounts of embryos, the chance of pregnancy is increased when the embryo is introduced earlier.
It’s a decision which can feel as though it’s out of our control and one which is very clinic led.
It’s important to discuss with consultants and embryologists, in order to find the solution which will, hopefully, have the best outcome for each person. We should also remember that whilst we can use research, statistics and data, to aid us in our choices, each situation is different, each embryo is unique, and each set of circumstances are individual.
Day 3 vs 5 day (blastocyst) embryo transfer – Questions and Answers
Below you can find ALL the questions asked by the attendees during the webinar on “3 day vs 5 day embryo transfer” and Dr Avilés’s complete answers. Having in mind the fact that some of you may have missed the webinar live or could not watch the video for some reason, EggDonationFriends have transcribed the entire Questions & Answers session for you to read. We believe that such reliable source of knowledge about embryo transfer day can be beneficial for everybody, no matter if you are just considering IVF treatment or you want to understand the difference between 3 day and 5 day embryo transfer.
Question: What age of the egg donor would you say is the best to have good quality embryos?
Our donors are between 18 and 25 years old. Sometimes we can have a donor who is 30 years old but this is not usual. We think this is the best age (18-25) because we can have a good number of good quality eggs.
Question: Is 8-cell transfer on day 3 or 5 the optimal cell count? Is 10 or 12 cell count best? (How many cells should an embryo have on day 3?)
If we transfer the embryo on day 3, it has to have 8 cells. If we transfer in blastocyst stage, the embryo will have more or less 120 cells. We can prepare the transfer on day 3 or on day 5, we can’t perform transfer on day 4, with about 16 cells – this is not the best option.
Question: We had 9 donor eggs of which 7 fertilised but only 1 made a good blastocyst to embryo transfer day 5. I wonder what would cause only one embryo to progress to day 5 blastocyst. The donor was 21 years old. We were told the one blastocyst was good quality.
We have to take into account the quality, too. Because the egg is the most important cell to form an embryo but if the quality of the sperm is not adequate or we have genetic alteration, then some of the embryos don’t achieve the blastocyst stage. Probably it’s not only the quality of the eggs. We need to know what the quality of the sperm is to see what the problem is.
Question: Is it true that sperm quality mostly affect embryo development from day 3?
It affects the embryo development from day 3, from the beginning and to the end. The sperm quality is very important. The genetic information determines if the embryos can achieve the blastocyst stage and result in pregnancy or not. The egg can solve some of the problems of the sperm, but not all of them. So sperm is important in the whole development of the embryo.
Question: Is there a specific width you prefer for womb / uterine lining for egg transfer?
We perform egg transfer with thin endometriums (6.5 mm), but the best width to perform egg transfer is about 8 mm.
Question: What is the main reason for poor fertilization after ICSI embryo transfer?
It’s a good question. The main reason can be bad quality of the egg, but also quality of sperm. If we have good quality eggs and good sperm, probably we will have good fertilization. But if one of them is not of good quality or the genetic information is not correct, there will be low fertilization rate. It depends on the quality of the eggs and sperm.
Question: I realise there must be a lot of different procedures depending on the recipient, but do you recommend egg hatching (assisted hatching)?
Egg hatching is something we can perform but it depends on the part of the embryos that is called pellucidum zone. It depends on the measurements of this part if we perform egg hatching or not. In egg donation we usually don’t recommend this technique because it doesn’t improve the implantation rate. We recommend hatching when we do frozen embryo transfer or when we do transfer in ICSI cycle in a woman who is about 40 years old. The quality of embryos is good and they are grade A, because they don’t give us a higher successful rate.
Question: Would donor embryos be same as frozen blastocyst day 5?
As donor embryos we can use frozen blastocysts or we can use frozen embryos on day 3. I have mentioned it before the devitrification success rate is 90% so there is no difference between 3 day vs 5 day embryo transfer in case of devitrified embryos. We usually transfer frozen embryos on day 3 or blastocyst stage because the possibilities are usually higher. But not all the embryos achieve blastocyst stage.
Question: I achieved 18 blastocysts from 3 cycles of my own eggs. Only one was euploid, a perfect grade A and failed to implant when transferred. Both my husband and I are 41 years old. My husband has sperm fragmentation of 15; 9% high fragmentation. Our IVF clinic believes that it is because the age of my eggs that we had 17 aneuploid blastocysts. Yet they say it is unusual that we achieved so many healthy blastocysts. Could my husband’s sperm also be a reason for the aneuploid blastocysts?
Your husband’s sperm can play a part, but the higher probability is that the reason is your eggs. We know that from the age of 35 the genetic material in our eggs is not the best. Probably the main cause of this situation is your eggs.
Question: What do you find is the greatest challenge in your day 3 vs day 5 embryo transfer success rates?
The biggest challenge is the quality of the embryo on day or day 5. If we have grade A embryo, the success rate could be higher than in grade C embryo. It is the same if it’s an embryo on day 3 or day 5. If we compare day 3 or day 5, we will have no chances for blastocysts most times. But the quality of the embryo is the most important thing.
Question: Which protocol would you suggest for egg donation if the sperm morphology is very low? ICSI? IMSI?
We always use ICSI for fertilization in egg donation program. IMSI doesn’t give us better fertilization rates, because it is something that can help only in very selective cases. When sperm morphology is very low, we will perform MACS that is a technique to improve sperm selection and fertilization with ICSI.
Question: If an egg fails to implant such as in the scenario above (Sheena’s case), is there a procedure that helps embryo to implant?
I think you are asking if egg donation is an option here. Egg donation is an option because probably the eggs are the problem. It could an option to get pregnancy and increase implantation rate.
Question: OK, thank you for your answer. I just needed to be sure that the problem lies in my eggs before we proceed to donor eggs.
I understand you. There is no way to be sure about that, but the probability that the eggs are the cause is really high, because of your age and statistically it is like this.
Question: We had a day 5 transfer (blstocyst stage) last week and I have an image. Is it possible to send it to you for an opinion on the blastocyst to see if it is high quality?
To evaluate an embryo it is better that the embryologists do that because, if you have a only a picture, we cannot see the whole development of the embryo and it is very important to know what was the development like because sometimes the cleavage timing or events that happen during development can make this embryo better or worse. It is like the videos that we have seen. If we only take a picture of the blastocyst in the blasto stage and don’t know what has happened during the development. I may classify it as a good embryo, grade A, but the development hasn’t been correct so with only one image I cannot evaluate it.
Question: I am perimenopausal. Does this in any way affect egg transfer success rates?
No. As you are not going to use your eggs and we can’t prepare your womb, there is no problem that you are perimenopausal for egg donation program.
Question: I had one good A grade egg that did not implant. Why?
Because of the embryo development. It is important to see the development of the embryo.
Question: If you are 44, is day 3 or day 5 transfer more successful?
Probably if you are 44, you will have only a few embryos. Probably less than three, with 8 cells on day 3. As I have said before, it depends on the number of embryos on day 3 with 8 cells. If you have more than three, probably embryo on day 5 would be better; if you have less than 3 embryos, probably transfer on day 3 is the best option.
Day 3 or day 5 transfer at PreGen
The webinar was presented by dr Avilés from PreGen, a fertility centre that is a part of Vistahermosa hospital where professor Rueda is a director. This Spanish clinic has over 34 years of experience in the field of ART and does over 1,650 IVF cycles a year. Their average success rate is reported at 67%. PreGen offers a wide range of infertility treatments including oocyte donation, IVF for same sex parents, single women, embryo donation, PGS & PGD.
What is important for many patients, PreGen offers fertility treatments to women with max. age of 50 and without any age limitations for men. Also, it offers much more than the British fertility clinics: assisted hatching, ICSI, embryo culture, time-lapse technology and even overnight accommodation for your oocyte retrieval appointment in Spain.
Embryo transfer day 3 or 5– how does it work?
If you are new to IVF, you should know that all embryos are assigned grades. This is done by the embryologist at the clinic. Their assessment is done based on the number of developed cells, the evenness of embryo growth and the degree of its fragmentation. The embryos with highest grade are usually chosen for transfer. How many embryos can you have transferred? The number depends on a few factors:
- the number of existing embryos,
- the patient’s age
- local legal regulations
- and other factors determined by the doctor.
British, Australian and Canadian patients can have a max. number of two embryos transferred. There are some exceptions allowed in non-typical cases. However, in American clinics, women under 40 may have multiple embryos transferred. Such procedure should be based on the doctor’s diagnosis of the patient’s condition.
It has been found in the studies that embryos which have reached the blastocyst stage in the lab usually have a higher chance of implanting successfully in the woman’s uterus. Doctors know that not all embryos will form the blastocyst outside of their natural environment – the womb. However, it is possible they could form a blastocyst inside the uterus.
3 day vs 5 day embryo transfer – what’s better?
It is completely natural that you want the best possible treatment option for and your partner, finally see those two lines on the pregnancy test and have a healthy baby. Also, it is completely natural that you have many questions and doubts. EggDonationFriends team understands that and aims to assist, educate and inform fertility patients who use our platform.
EggDonationFriends do receive a lot of questions about the issue of whether it is more beneficial to transfer blastocysts rather than early 3 day embryos. The most common questions are:
- How many day 3 embryos make it to day 5 blastocyst?
- What are day 3 embryo success rates?
- What are day 5 embryos success rates?
- Does the clinic perform day 3 and day 5 embryo transfers?
- What are the risks of day 3 embryo transfer?
- What are the risks of day 5 embryo transfer? (identical twins/complications such as monochorionic twins or monoamniotic twins)
- Is a 5 day embryo transfer better?
- What is the difference between 3 day and 5 day embryo transfer?
These questions and many more were answered by Dr. Avilés during the webinar. During the presentation you could find out what the doctors’ recommendations are for day 3 or day 5 transfer and which one is better in what circumstances. This is certainly a decision that requires careful diagnosis of the patient’s case and careful thought on the side of the doctor.
About the author:
Dr. Carmen Aviles is a gynecologist specialist in reproduction at the Reproduction Unit of Clínica Vistahermosa/PreGen in Spain.
External resources you may be interested in:
Day 3 embryo transfer versus day 5 blastocyst transfers: A prospective randomized controlled trial. – Turk J Obstet Gynecol. 2017 Jun; 14(2): 82–88.
Published online 2017 Jun 15. doi: 10.4274/tjod.99076
Impact of day 3 or day 5 embryo transfer on pregnancy rates and multiple gestations – Fertility and Sterility – 2017 / Volume 91, Issue 5, Pages 1717–1720
Cleavage-stage or blastocyst transfer: what are the benefits and harms? – Fertility and Sterility – 2016 / Volume 106, Issue 2, Pages 244–250
The importance of the cleavage stage morphology evaluation for blastocyst transfer in patients with good prognosis – J Assist Reprod Genet. 2014 Aug; 31(8): 1105–1110. Published online 2014 Jun 4. doi: 10.1007/s10815-014-0266-4