Hi Debi---
I'm in nearly the same shoes as you. (except I'm not using donor) We have 5 expanded blasts frozen. 2-2-1 (straws.) The endocrinologist explained it to me that it meant that they were about to "hatch" on their own, and likely would during or immediately after the "thaw." He said that it meant they were developing excellently and was very enthused by this knowledge. Furthermore, I asked about "assisted hatching" and he said that they would do this if they didn't do it on their own, but they very well might not need any assistance!!
Now, my DH and I have been doing the "whatifs" scenario on number to transfer as well. They suggest at our clinic to transfer 3 quality embryo's for FET's (2 for 'fresh") (Keep in mind every clinic is slightly different, obviously) Anyway, they told me that to transfer 3 frozen embies....they give approx. 37% chance of having a singleton/24% chance twins. To transfer 2 embies, 23% chance singleton/20% odds twins.
To ME, the difference is worth trying to transfer 3....but, that's just me. (The RE said she wants to transfer 3....the embryologist thinks we should stick to 2....so, there's discrepancy between two docs....just to further confuse me, I guess. The embryologist said we'd be asking for triplets....I doubt it, but....we'd be ok if that did happen.)
Now, the dilemma: if they thaw out 2 straws to get 3 embies and 2 make it....we must decide: a.) thaw out additional straw and then hope that you have 3 good ones.....but know that you might have 4 and then you'd have to decide within MINUTES to transfer 3 vs 4!! b.) go with transferring the two you have and leave the other two.
We still don't know what to do. DH has a feeling we're asking for trouble to transfer 4, should that situation arrise. I am not worried. I think things will happen how they're meant to on that day......but anxious to get there and see what happens! Like you, we could not do the selective reduction----but, truly...I think the odds of having quads even if you do transfer 4 are pretty slim, so, my instinct says to GO FOR IT and hope that 2/4 "take"!
That's just more info to throw in your bag. Sounds like things are going great though!! Many congrats and you're right----what a special person to donate those fabulous embies for you!! Good luck!!!