You'll only know how many embryos have survived the thaw once they are thawed. The way they check is that they see whether the number of cells is the same as when they froze the embryo.
If you have them frozen in 2 separate straws, you may want to thaw only 2 and then if they both survive, to transfer both. Once you've thawed all 4, it will be a harder decision - especially if they all survive the thaw.
If you're under 35, transferring 2 is recommended - at over 35, 3 can produce higher pregnancy rates.
Good luck!
Rachel Inbar
(mom to twins from frozen embryo transfer)
www.FertilityStories.com
