does not have a high rate of error, I think closer to 10% if I recall correctly? That is due to the fact that they now know embryos tend to "self-correct" ie the embryos can proceed even with some abnormal cells, letting those become the placenta, and the normal cells become the baby. So in cases where that is the cell that you have sampled (out of the 8-cell embie on day 3), you would lose that embie that might have "self-corrected." No false negative rate, which was more important to me, along with the fact that PGS now tests all 23 chromosome pairs (used to be 6 or 8 pairs for only the most common errors with PGD). If you do the embryo biopsy on day 5 (which then requires a freeze-all as you won't have results in time for transfer), this risk of false positives is virtually eliminated - as it was explained to me, so this is just my understanding of recent developments.
After 3 DE mcs (with one DE live birth in the middle), we did CGH on yet another fresh cycle, transferred one normal embie and are 20w pg with a singleton. We had enough embies that I could live with losing 1 in 10 in error, so we did test them on day 3, had results back by day 5, and did the fresh transfer. I'm REALLY glad we did it, as it has also allowed me to relax quite a bit more and not head into NT scan and such with any fear, more like just a fun u/s
. Even better, I knew when I p'd on a stick that I was having a girl LOL (either would have been equally wonderful, I just thought it was a kick to know that early and be able to say "SHE is giving me heartburn already.")