We hadn't told anyone that I was pregnant yet. When I was first went into the ER, my husband called both of our sets of parents. Our siblings got filled in as well. That's it. Those are the only people we told. I understand that some people in my situation would probably want to tell all of their friends and would need to talk and get support.
For us, we just found it too painful to have to keep explaining it to everyone. There was nothing that they could do to help, and I really didn't want any platitudes. It was hard enough to process to ourselves that it had been an ectopic pregnancy and that our baby was gone. Explaining it to lots of other people (and--even worse--having word get around so that acquaintances brought it up to us) was just too much. I needed to recover from the surgery anyway, so we just kind of dropped out of society for a few weeks. (It was easier because we had planned to be out of town about now, so people just thought that we were on summer vacation like everybody else.) That's all of the people we told, although I know that my mom did tell some people (at least a few relatives, but I suspect many more of her friends as well).
A few people who know have been fantastic, and I will be forever grateful for their unconditional and absolute sympathy and love. Some people, though, just don't know how to react. Perhaps worst of all, my parents seem determined to just avoid the subject completely. They will discuss my physical recovery (as briefly as possible) if I bring it up, but there's been absolutely no mention that this was their grandbaby. That's hard too.
So here's my advice. If you know someone who suffers through an ectopic pregnancy (or miscarriage, for that matter), don't avoid them or keep bringing the subject up. Just be ready to sit down with them, let them talk, cry with them, and then give them a hug if you're the hugging type. Maybe bring by some food for them.