Is day 3 better for the embryo transfer than day 5?
Pros and cons of transfer on day 3 and day 5? What determines the choice of transfer day and how the decision is made? Why sometimes day 3 is the best option? What about clinical results? Is birth rate on day 5 embryo transfers higher?
Experts answers these questions in 3on1 #IVFANSWERS. Watch:
• Dr Roxolana Semchyshyn, M.D., Head of IVF department, Intersono IVF Clinic
• Dr. Luboš Vlček, Physician, GYNEM Fertility Clinic Prague
• Buse Karanlık, Embryologist, Cyprus Dunya IVF Clinic
Answer from Dr Semchyshyn, M.D., Head of IVF department
We can have two options: day 3 embryo transfer and day 5 embryo transfer. At Intersono IVF clinic, we have a higher clinical pregnancy rate when we are doing the embryo transfer on day 5.
Why? We have several reasons for that.
First of all, this is Mother Nature. During natural conception, the embryo drops into the uterus on day 5. So it is a natural situation when a day 5 embryo is in our uterus. During natural conception, the embryo is in the tubes. So it is not a natural situation when a day 3 embryo drops into our uterus. Therefore, higher clinical pregnancy results are on day 5 embryo transfers.
The second reason is the option for selection. It is the oocyte that is responsible for the first 3 days of the embryo development. The sperm is responsible for the next two days. In that case, when we have a sperm factor, sometimes we can have the good embryo on day 3 but we don’t have the blastocyst stage on day 5. Therefore, if you transfer a day 5 embryo, we have the option of selection and we can choose the best embryo.
The third reason is the opportunity to do PGS screening of the embryo. If you’re talking about a day 3 embryo, on that stage the embryo consists of cells. It is an ideal situation when we have 8 cells. When we are doing the biopsy on these embryos, we’re taking out just 1 or 2 cells. In that case, when are doing the biopsy on those embryos, we can miss some pathology. For example, in one cell we can have the normal chromosomal structure and the other can contain the abnormal chromosomal structure.
When we are doing the biopsy on day 5 embryos, we don’t have separate cells. In that case, all cells are equal and we can’t miss the mosaic embryo. Intersono IVF clinic recommends you to do embryo transfer on day 5 to get higher chances for pregnancy.
Answer from Dr Vlček, Physician
The natural embryo selection is helping us to transfer the healthy embryos. That’s why we are usually waiting till day 5. This is actually the prevention against the repeated D&Cs because of miscarriages. But I think in the individual cases, if you do not have the option to make a selection or choice for more embryos, it is better to transfer them on day 3 rather than waiting to day 5.
Answer from Karanlık - Embryologist
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.