Just thought I'd rant share this with you all, as before yesterday I was totally ignorant of the above fact. Was having contractions for five hours - am 33 weeks - was bloody scary, only to be told that I have a water infection, and that's what was causing them. Can lead to premature labout too, apparently.
Wish I'd been told that before I was running around like a headless chicken screaming "He can't be coming today, he can't be coming today!!!"