IVF question---my bro and SIL just had a transfer this week (3rd IVF attempt). Forgive me for those of you going through this if I am not getting my terminology correct. Anyway, they transferred an "8B4" embryo. is that good? I am DYING for this to work for them and I don't want to pepper them with questions. Can anyone explain?

I've never heard of an 8B4 embryo. I transferred only 1 BC embryo and it worked (so far so good). But it depends on their circumstances, fertility issue, age, etc. At the end of the day, I've heard of 2 AA embryos not taking, so you just never know. It can't just be based on having the best quality embryos or I wouldn't be pregnant. Good luck to them!