hmmm i'm not really sure, but can only tell you my recent experience... first baby came on time, no BH or niggles at all.... second baby i had TONNES of BH, and on the day i went into labour, i had constant BH two minutes apart all day, hospital said it was nothing but i knew deep down it was pre-labour as they were every 2 minutes.... started at 8am in the morning, and by 4pm they were hurting, by 7pm ish i was at hospital in full blown labour, bubs wasn't born til 5.50am next day...

anyways i think there is always a chance it is pre-labour..... sorry i haven't been much help have i!?