When did this Hollywood "baby bump" obsession begin?

I feel like celebrities used to have babies in (relative) peace and quiet. They might have been photographed with kids once they had them, but pregnanacy didn’t used to be this huge hollywood story—it happened behind the scenes. I don’t even remember the word “baby bump” being used until a few years ago, and now it’s the cover of People magazine almost every week. Is it me, or is this a relatively new cultural trend—obsession with celebrities’ pregnant bellies? When did it start? And what does it say about our society/culture?