Twin mamas-NT scan

Sascha3

Have any of the twin moms had theirs yet?  I go in Monday.  I was wondering if they are able to tell at this point whether they are sharing a sac and placenta, or seperate sacs/one placenta, or 2 sacs/2 placentas?

I know if they share one or the other they are identical.  But what shocked me was that even if it is 2 sacs and 2 placentas, there is still a 25% chance that they are identical.  So if they end up being the same sex I may not know if they are identical or not without DNA testing.  Obviously one of each sex would answer that question:)