We did that because we transferred two of the highest quality blasts that our clinic rarely sees during our fresh cycle...it was a perfect cycle, excellent lining..etc but we ended up with a chemical.
We had 8 frozen..so for our next FET we thawed 3 of our blasts and all made the thaw...two were really good quality...one a hail mary...we were warned of twins which we would have been happy with but we ended up with a beautiful singleton Ds.
2 years later we did our 2nd FET and thawed out 3 again...all three survived the thaw and this time they were all of great quality...our embryologist told us that they looked as good as the day she froze them.
Just prior to the transfer my Dr. asked again if I was sure I wanted to transfer 3...and warned me of triplets or at the very least twins. I reminded him that we had gone through 5 blasts of this quality or higher and only had a singleton so I wanted to take the risk...to up my chances of just getting pg.
When my beta came in very positive with high numbers I had a feeling we had more than one so at our first u/s at 7 wks I wasn't exactly shocked that we had twins on board. Very happy with the results and we still have 2 frozen left.
Our clinic tends to be very conservative with the number of embies transferred since they want to avoid multiples at all cost...but there are so many factors to take into account than just the number of the embies...the quality...if they are day 3 or blasts, if the lining is excellent, if the blood flow to the uterus has been proven to ensure good implantation can take place.
In the end you just have to listen to your gut though and askyourself if you will be okay with carrying twins or maybe more, and raising them.
My Dr. asked me during our last FET..if we had triplets would we selectively reduce and I told him we would think about it...b/c I knew that is what he needed to hear to alleviate his fears....but thankfully we didn't have to make that decision.
This pgcy has been going great...has been really no different than any of my singleton pgcies so far....except I've gained a bit more weight and am measuring about 6 weeks more than I am at almost 23 wks.
this is a good question though to ask your clinic before you choose to work with them so that their philosophy and yours jives.
blessings from Hope