I did not start getting them until really recently. Like the baby hiccups, it turned out I had been getting them for awhile but just didn't know what they were. I thought it was the baby pushing on me and/or my clothes constricting me. They were just really mild. When I got a couple stronger ones, I thought "OH!! That's what those are!"
I still only get noticeable ones very infrequently, like not quite every day...