Embryo Biopsy or PGS

Hopefully, you’ve read in my previous blog, twin pregnancies are not optimal and can be associated with significant complications, for both mother and baby. In an attempt to eliminate triplets and minimize the chance of twins, our clinic has adopted the practice of elective Single Embryo Transfer (eSET) for the majority of our patients. Our general practice is to freeze all top quality embryos on day 5 or 6 after retrieval, and then transfer one of these top quality embryos individually until we have a successful outcome. The upside to this practice is that we have reduced our twin pregnancy rate for IVF patients to 6%. And although our overall pregnancy rates, per cycle, have remained very good, our pregnancy rate per transfer is lower than when we routinely transferred two embryos.
This makes sense if you realize that about 50% of the top quality embryos that we freeze have an abnormal chromosomal content. They have either one too many or too few chromosomes, and in some cases, deletions or additions to part of a chromosome. These abnormal embryos will not result in a normal pregnancy or will end in miscarriage. In rare cases they may give birth to an infant with a birth defect. Unfortunately, we are not able to distinguish, by microscope alone, which of our top quality embryos are chromosomally normal. The end result is that we have a live birth rate of 35 to 40% if we transfer one top quality embryo without biopsy.
Although this is an acceptable success rate, it still means that almost 2/3 of our patients will not have success even though we transfer what appears to be a top quality embryo. This translates to the need for 2 or 3+ embryo transfers of top quality embryos before we achieve a live birth. This can add up to considerable cost, not to mention heart ache, by having patients suffer through additional failed frozen embryo transfer cycles and/or miscarriages.
For some time now, the technology has been available to biopsy embryos. This allows us to determine which are chromosomally normal and which are not. Transfer of a chromosomally normal embryo of top quality doubles the chance of a live birth, from 35% to about 70%. The biopsy and embryo analysis is usually not covered by insurance and, until recently, the cost of this procedure has caused many patients to opt against it. We have recently been able to dramatically decrease this cost and, as such, it has become a routine part of our IVF practice.
To summarize, there will be some patients who have zero top quality embryos. In this case, biopsy is not a possibility and we may elect to transfer the best embryo, as determined microscopically. Many patients, however, will have 1 or more top quality appearing embryos. If we transfer one of these embryos, without biopsy, the live birth rate will be about 35%. If we perform embryo biopsy and transfer a chromosomally normal embryo, the live birth rate jumps to 65 to 70%. Again, this is good news for everyone…..
NOTE: Embryo biopsy does NOT make the embryo better. It merely reduces the number of transfers needed to achieve a successful pregnancy. There will be times when all the biopsied embryos will be abnormal and we will have nothing to transfer. As difficult as that may be, it avoids one, or sometimes many, fruitless transfers which will result in negative pregnancy tests, all which add up to additional and unnecessary heartache and costs. If there are no normal embryos, we feel it is best to move on to the next phase, usually another retrieval cycle, in hopes of acquiring 1 or more chromosomally normal embryos.
Dr Springer

Leave a Reply

Your email address will not be published.