I don't mean the odd post here and there, I mean daily or more frequent updates/photos of scans, things you've bought or made for the baby, the "delicious" glass of Appletize you're enjoying, how sick you're feeling, how big your bump is, and so on ad infinitum?
Not only is it more boring than a parking thread on AIBU for all the friends in whose newsfeeds your updates appear, but for many women of childbearing age there's a good chance your peers/friends may be TTC, or unable to conceive, or wishing they had a partner to conceive with.
Almost as bad are the parents who detail every tiny little boring thing their child has done that day. I'm still waiting for someone to Instagram a picture of their baby's shitty nappy.