Blastocyst Vs Day 2/3 transfer

[sushee]

I am not a doctor and don't purport to be one, but often this question gets asked over and over, so I thought I'd share some of the notes I made when discussing this issue with my doctor, and hope that it helps someone make their decision about how they wish to progress with their treatment.

Also having said that, many clinics don't do anything but blast transfers, so for some, it is a moot point anyway.

Why have a Day 2 transfer?

1) Because the rate of loss of embryos at Day 3 (approx 8 cell stage) is quite low, you often have as many embryos to transfer, or cryopreserve for later, as was initially fertilised. This often means that should 10 eggs fertilise and you transfer 2, you will then have 8 embryos in storage for further cycles without the emotional and physical strain of repeated IVF stimulated cycles. It also means being able to do back to back cycles, which is not possible with stimulated cycles.

2) The chances of success with a Day 2 transfer are very respectable, at around 20%. This may be more or less depending on your age group or reason for infertility, but is by no means anything to sneeze at. This represents a 1 in 5 chance of falling pg. So, again, with the above example, your chances of potentially falling pg in the next 5 cycles (and this could be the next five months back to back) are pretty good.

3) The chances of a cancelled cycle due to the loss of all embryos is very, very slim.

Why have a blast transfer?

1) Most embryos have all the necessary material to survive to day 3 (or 8 cell) stage, whether or not they are viable. It's only the more robust and viable embryos, however, that make it past this stage. Therefore, with a blast transfer, natural selection tends to 'eliminate' the embryos that would have had no chance of becoming a viable pregnancy. While there is no guarantee, of course, that embryos that make it past the day 3 'hurdle' will become pregnancies, the possibility of this becomes greater (at about 45-50%, I believe)

2) Blast transfer allows for genetic testing, and this can be beneficial in the case of patients who seem to have difficulties with implantation, or with recurrent miscarriage.

3) Fewer transfers can mean less stress and emotional 'up and downs' than more frequent Day 2 transfers. For someone who's endured many cycles of IVF, this can be an emotional 'relief' to know that you may have fewer transfers, but each has a better chance of success.

What I guess everyone has to consider is that because of the embryo loss associated with blast transfer, it may take as long to achieve a pg, and as many cycles, as it would have with a Day 2 transfer. This is why most clinics will not attempt a blast transfer if embryo numbers are low to start with, as often it is emotionally and physically beneficial to the patient (and maybe the embryos as well!) to get to transfer rather than potentially lose every embryo and have to cancel their cycle. In this way, there is no benefit to a blast transfer if only 1 or 2 embryos are available at day 2, except for intellectual reasons as to whether your embryos were surviving past Day 3.

In my case, we decided to go to a blast transfer with only 3 viable embryos because, after 7 failed cycles, we needed to know if they were making it past that Day 3 'hurdle'. I think we would have done it had we only had 1 embryo. And if this cycle failed, we would have moved on to genetic testing to see if there were genetic problems with our embryos.

I don't think I've covered every single pro or con, but I hope this gives you some idea if you're trying to make up your mind. If anyone wants to add anything or dispute anything, please feel free, I won't take offence or anything. Just wanted to share my experience.

Hope it helps.

love
sushee