Welcome Kazy! Good luck for your scan. They are so nerve wracking after a loss. I think I have a love hate relationship with them!
It is so tricky to know when to tell people. Maybe just see how you feel at the time, whether it's after a scan or not. You might find it helps to get through your original EDD or it could make it worse. I guess you'll know when the time is right.
If we could I would wait till at least 12 weeks, which weirdly is the day after the EDD of the MMC. But since the MMC people know we're TTC and as soon as they see me not drinking it'll be obvious. Also, I'm wearing baggy clothes because of the bloat!! I'm seeing my mum on Friday for her birthday and I'm pretty sure she'll know. I would love to tell all our parents because I know how happy they will be, but if it ends in mc again it'll be so hard so I'd rather wait.