The membrane is really, really hard to see in monochronic/diamniotic twins (what mine where). It took about forever when they did the anmio because they had such a hard time finding on the ultrasound where the membrane was and that was with the latest/greatest equipment at BC Chidren's hospital and high level perinatolgists when I was 20 weeks. Monoamniotic twins do happen - but I think 11 weeks might be a little early to tell for sure.
For twin pregnancy support try the expecting forum at
www.twinstuff.com - I'm CherylE on those forums (usually found in The First Year and and Twins 1-5 forums right now.
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~ Cheryl ~ single mama to
Melissa (9), Michael (8), Madeleine (7)
twins Megan & Maribeth (4)
