I had them like that for the last 3 bubbas.. and when labour did it, it hit fast!!!
I had them starting around 34 wks, and went over with most, so I dont think its an indicator of early labour, more of half the work is done by the time you ARE in labour!!
Last 3 labours were 1.5 hr, 45 mim, 1.5 hr.... from first pain. So although I dont think they are harmful, I think they do do something....