I had period pains basically - but on five minute intervals... so went in to be checked, and while their trace machine deemed I wasn't in labour, swabs showed I was leaking amniotic fluid - so got the first shot of steroids and was kept in for the follow-up shot.
Pain got worse - because of leaky waters they wouldn't examine me, fobbed me off with two paracetamol and shoved me on a ward... trace machine still deemed me not in labour officially... lots of waiting around - pressure like I needed to poo (she was back-to-back, having spun around to decide to make things as difficult as possible - little oik!), so sitting on the loo, about 20 hours after I'd gone in there - pop-woosh waters went completely... at that point they WOULD check me again and found I was 8cm dilated.
Cue a massive trolley rush back down to the labour ward (the midwives and ward staff were pushing, they didn't even wait for porters... I got bounced off every corridor wall as none of them could push in a straight line) - and FINALLY some gas and air! Until my waters completely went, rather than the slow puncture I had had - no one deemed me "in labour" as such at all!