I posted last week after having a 9 week private ultrasound which suggested monoamniotic twins. Ever since I have read just about every research paper ever written about them 
I really have scared myself silly.
At 9 weeks, the main reason the sonographer suspected mono-mono is because she thought she could see only one yolk sac. I understand that if she's right, my chances of a misdiagnosis (finding a dividing memrane later) are very slim. But the more I look at my pictures compared with other 9 week scans, the more I feel that they're really not very clear and the one "yolk sac" that was identified doesn't even really look like the clear halo yolk sacs I've seen online. I'm not criticising the sonographer or doubting her skills at all. To be fair we went to the 15 minute appointment expecting to look at one baby, not two. She didn't have much time to look around. It was also abdominal, so I gather less clear than an internal would have been.
Here are the best pictures we got - I would love some thoughts (anyone's at this point - I am going mad!)