Is the quality of embryo on day 3 a key predictor?
Should I be worried if embryos on day 3 are poor quality? Are there any chances it will develop to good quality blastocyst on day 5? Why it may not be the most important prognostic factor at all?
You will know all about it from our experts in 3on1 #IVFANSWERS:
- Dr. Luboš Vlček, GYNEM Fertility Clinic Prague
- Buse Karanlık, Embryologist, Cyprus Dunya IVF Clinic
- Dr Roxolana Semchyshyn, M.D., Head of IVF department, Intersono IVF Clinic
Answer from Dr Vlček - Physician
This problem is very individual. Even the embryos of poor quality may become a healthy child. So the best selection time for the transfer is the day 5. And if we have more embryos on day 3, we advise the patient to carry on with the cultivation and select embryos later on day 5.
Answer from Karanlık - Embryologist
Firstly, embryo morphology correlates with the successful implantation. For an embryologist it is really difficult to predict if an embryo can go for an implantation or not. Sometimes bad quality embryos can go to implantation surprisingly and sometimes a good quality embryo can fail. So it is not a predictable thing. Day 3 embryos have higher aneuploidy rates compared to day 5 embryos. So it is really important to go to day 5 to see which ones are going to form the blastocyst. Basically, embryos on day 5 can have a natural selection process themselves. The ones that can go on to day 5 basically are naturally selected and eliminated. The successful ones can go on to day 5, make blastocysts and hopefully – pregnancy.
Recent research shows that actually low scoring day 3 embryo, which are not considered to be transferable, can give a good result of the blastolation and the live birth. So according to literature, it is ideal to go to day 5 and make a day 5 embryo transfer.
There is also a second parameter, that supports the idea of the day 3 embryo culture to day 5, is the uterine environment. When we are thinking about the normal conditions in naturally conceiving people, the embryo development takes from the fallopian tube to the uterus. So on day 3 and day 4, in the ideal conditions, the embryo is still in the fallopian tubes and not in the uterus. According to some researchers, the ideal location for day 3 embryos is not the uterus. Basically, the synchronisation of the uterus with the embryo is not really suitable for day 3. So according to some embryologists and some researchers, making day 3 embryos go to day 5 would be more synchronised with the uterus. So day 5 transfers would be more ideal than those on day 3.
So on day 3, if we have poor quality of embryos, it is ideal to go to day 5 to see if there are any transferable embryos to select the best ones. And then transfer them with a more synchronised uterus on day 5.
Answer from Dr Semchyshyn - Head of IVF department
First of all, day 3 is the intermediate stage of embryo development. Day 5, the blastocyst stage, is the final stage of embryo development when we finally understand if we have a good quality or a bad quality embryo. We can have the situation when on day 3 we have a bad quality embryo but on day 5 we receive a blastocyst of intermediate or even good quality. We can have also an opposite situation. On day 3 we can have a very good quality embryo, but after day 4 a sperm factor can influence the embryo quality and we will not receive a blastocyst stage embryo on day 5.
Intersono IVF clinic recommends to cultivate all embryos up to day 5. On that day we can have a better embryo selection and we understand that we will transfer only good quality embryos. This is the final development stage of the embryo.