I think we need to be very careful actually to go down the route of thinking that just because someone has suffered a loss, any loss, that gives them justification to treat others however the hell they want. It doesn't.
Yes of course miscarriage is heartbreaking. Yes it is horrible to ttc unsuccessfully (I did so for around five years for my second child and was never successful). But while someone should be understanding of the fact especially if they are just pregnant at the time of the loss, they haven't actually done anything wrong.
It's not wrong to be pregnant.
It's not wrong to talk about being pregnant.
It's not wrong to be upset about having had a miscarriage.
But it is IMO wrong to start ending friendships over it and then expecting hose friends to accommodate and be supportive and understanding of that purely on the basis that there has been a miscarriage.
Because at some point that person may well fall pregnant again, and how understanding do you think they will be if the friends they once had no longer want to know on the basis they were snubbed for doing nothing wrong?
If someone is that deeply traumatised by something which is unfortunately so common as to affect one in six pregnancies under twelve weeks, they should be seeking professional help to deal with their issues, not expecting their friends to be obliterated out of their lives and to be understanding of that until such times as they feel they want to talk to them again.
Being pregnant is not a crime.
I agree with bringmesunshine, miscarriage/infertility is used as a justification for some seriously shocking behavior, ending friendships, refusing to go to or even letting your dh go to family gatherings? I suspect in fact people would be a lot more understanding and sympathetic if those going through it weren't quite so expectant of how other people should behave and understand. Pushing people away like that achieves nothing.