The clinic I used would only grow to blast if there were more than three embryos at day three. With your stats, they'd be willing to risk it, but only do it if you are comfortable doing so. I would think that if the scientist is suggesting day 3, then they aren't terribly confident of getting too much to blast. Is this a PGD cycle and will day three transfers mean you can't test the embryos? Or are you just aiming to transfer something and risk the genetic problems? I guess that's all stuff that needs to be considered for you.

From my history - I had two cycles where I was badly hyperstimulated - 26 and 32 eggs respectively. We had 15 and 20 fertilise and of those we had 4 and 7 make it to blastocyst. Keep in mind that my egg quality was fairly crap due to the hyperstimulation! All were frozen and only two from each cycle successfully thawed to be transferred. I had three miscarriages and one negative from those transfers.

My third cycle - only mild OHSS, so I was able to have a fresh transfer. 20 eggs, 12 mature (I'd been taken a little early to help avoid the OHSS) but only three fertilised. One is now an 18 month old toddler terrorising his father in the kitchen and the other two are still frozen and waiting... I'm not a big fan of blasts, but others have very different outcomes.

BW