Girls, hi! A couple of days now I've been feeling periodic pain in my …

Girls, hi! A couple of days now I've been feeling periodic pain in my lower back and stomach cramps, like contractions, then it lets go. It seems like training has started, I think. Now the question is, who had their baby after the start of the training, or is it just an optional sign of imminent labor? I don't remember this with the first birth, but with the second ones, yes, but something doesn't come to mind anymore.