I think it depends on when they were frozen also - I know MIVF often freezes them at 2 days as the success with rethawing is very very high. They actually have excellent statistics. I have just had second FET and both thawed out well.Both thawed as 2 days and split again at day 3 one to 8 and the other to over 9 (which is the one I am currently in 2ww with). You need to research the clinic and the methods I think - but what everyone has said is right if the embbie is going to make it - it will - which leaves me at a loss as to why if its strong enough to thaw out - why it wont implant? Third time lucky I guess....