D.C.
I see no responses, yet, before me (how interesting).
I have been there. I had two miscarriages before finding that I needed surgery. And now have three healthy boys (no longer babies, though).
If I were in your place, I would approach my friend in a casual way then ask for a minute to discuss something personal (I would try to imply that I want to say something casually, but in a sincere kind of way). I would say I care for her and really want to give her all the support I can give. Then say, in a plain kind of voice, that I just recently found out I was pregnant and due xx/xx/xxxx. I would mention that I have been hesitant to mention the news to her because I really care about her and her feelings.
I would follow up with a question, like, I hope you keep trying and if is there anything I can do to help her feel okay (she doesn't have to feel overjoyed or pretend to). I would be very understanding if you feel like visiting another friend instead of me while I'm pregnant or at some of the times during this time.
My thoughts are 1) give her the news one-on-one, 2) tell her about feeling hesitant to mention it, and 3) repeat that she can still count on you for support and friendship.
I had problems getting very sad when someone fairly close to me, like in the family, would announce the pregnancy to everyone in the room, while I was among the group. Talking to me one-on-one was much easier to handle. I could be happy for my friend, have a sad moment, and still turn it around, reminding myself that it isn't my friend's fault that I was having difficulty getting pregnant.
Sorry I rambled on so! I think I said everything at least twice! :)
You are welcome to send me a personal message if you another question about this.