I hadn't told anyone at work that I was pregnant with Noah and had plans to tell them after the scan. I lost Noah and went back to work a week later. My boss knew I had lost a baby but being an older male he obviously assumed I wasn't very far into the pregnancy. Straight after I went back to work I had to do a training course at another office and when I got there, I was confronted by the receptionist who had the most gorgeous pregnant belly. I felt myself choke up and I felt sick. I couldn't stop staring at her belly. I asked her how far into her pregnancy she was and yep, she was as pregnant as I should have been.
It was really difficult and I hated every week I did my training course there. It didn't get easier for me. The only tiny bit of relief that came was due to the fact that she was having a girl.
My sister was 6 weeks behind me when I lost Noah. She was having a boy. I became really protective of her and her baby. As hard as it is for me to admit, although I love my nephew to bits my bond with him isn't as strong as the one I have with his older brothers. I think I tried to protect myself too much. Even just yesterday I looked at photos of him and thought "That's how big Noah should be now".

I personally think it is best to feel out the situation. If someone is pregnant and their friend looses a baby, there is no harm in asking them how they would feel about having a visit from a pregnant friend. I think I would prefer to be asked than to be avoided.