I am sure it is possible not to know if you break your water. It can be as small as a little trickle or a huge gush, and many women think they be leaking urine. So my question is.... what if I sleep through labour?

I've heard tales of women sleeping through early signs of labour eg water breaking but once the painful parts of labour start happening like contractions, apparently it's quite hard to ignore those pains. My friend was asleep when her water broke but she was awaken by the worst tummy ache in the history of tummy aches (her words not mine). She was rushed to the hospital and gave birth within hours. It's very rare to have a mother sleep naturally sleep through labou, I feel.