emerald - not sure if this is the info you are after, but both times i got a bfp it was with a day 2/3 embryo. one was 8 cells, one was 6-7 cells. unfortunately didnt work out, but a bfp is a bfp. i have since had 3 blast transfers that havent even registered a blip on the system. i am seriously considering going back to 2/3 day transfers too.