I kind of sort of did by accident.

A bunch of friends with babies got together, and since there are so many babies among our group of friends, so close in age, I made a joke that someone must already be pregnant with the next one. I saw one couple exchange a very telling look, but I didn't want to make them awkward so I tried to cover it up and move on (but I'm so not subtle). Luckily they were planning on telling us then anyway and I provided a nice opening