Can anyone explain to me what stage 2 blastocyst is, if familiar with this topic? I understood there are three stages of blastocysts.

I googled it but the information i found is related to grades of blastocysts not the stages.

The reason for asking is that yesterday i transferred a 5day blastocyst and they did not give me the grade. I asked and they told me that we don’t grade the blastocysts for fresh transfer but yours is stage 2

Blastocyst ( out of three stages). Honestly, not clear to me what she meant.