Improving Implantation: The goal of SEET using PGS
Posted Sep 09 2013 11:09am
The Holy Grail of IVF is having an IVF pregnancy rate that approaches 100% with a low rate of pregnancy loss...Now, I know that some clinics advertise pregnancy rates of 120% (just kidding....I hope) with a 100% money back guarantee and a free toaster in the color of your choice... All kidding aside, the goal is a laudable one and the Devil is in the details of how to achieve that goal.
Back in July I was in Santa Barbara for the Annual UCLA IVF meeting. This gathering of medical professionals is a truly excellent opportunity to interact with colleagues and learn about what constitutes the "State of the Art...in ART." A lot of programs are using stimulation protocols for IVF that rely upon Lupron (GnRH-agonist) to trigger for egg collection instead of HCG. We have been using this protocol for over a year now but quickly concluded that patients using this protocol may be best served by freezing all embryos and then performing an FET the following cycle. This protocol reduces the risk of OHSS to near zero but the benefit of that risk reduction also results in such a precipitous drop in hormone levels following egg collection that implantation rates also drop significantly. Hence the logic behind freezing all embryos after egg collection. Indeed, this year the theme at the meeting was almost uniformly "Freeze, baby, freeze."
However, the Holy Grail remains elusive. If we perform PGS on the blastocyst stage embryos then the implantation rates can be improved markedly and the miscarriage rate reduced as well. So if the implantation rate at age 38 is typically 12% and we can increase this to 65-70% with PGS. So we are clearly making some real progress.
But why is the implantation rate not 100%? That is the $64,000 Question.... Data presented at the meeting indicated that performing the biopsy was not the culprit. Other possible explanations are single gene defects that are not currently detected, the embryo transfer procedure and the receptivity of the endometrium (hormonal or possibly immunologic).
So we are aggressively pursuing the concept of Single Euploid Embryo Transfer (SEET) which is a fancy way of describing the transfer of one genetically proven normal embryo. Although an implantation rate of 65-70% isn't 100%, that may represent the best that we can do....but stay tuned.