I'm 37 and a bit weeks and they're really starting to wind me up now. I've had them since 16 weeks but just a couple a day. Last couple of weeks I've had the odd run of mild ones on a night.
Yesterday I had 7 hours of them 5 minutes apart, with my whole bump going rock hard. Stopped at tea time for a couple of hours and then started getting period type cramps. Thought this was it! Turned into painful contractions till I finally fell asleep and they stopped 
This is my 5th baby, you would think my body would have a clue by now!