I don’t know why it irritates me, but another of my pet peeves is when an infant is referred to as a “new baby.”

I listened to an audiobook that kept referencing couples “with a new baby.” I also hear this weird adjective used often on the radio.
It is like the person isn’t actually thinking about what they’re saying.

I’ve never heard of an old baby. Or a used baby.

Either it is a newborn, or it is a X-month-old baby. Even a little baby would be fine with me.