Not sure about other mummies, but before i give birth thr was no sign at all. just water bag leaking the day before n slight contration which i thought was bcoz i too heavy so tummy pain till i saw "red".
Its ok as long as baby is ok inside, mayb too comfortable so dont want to come out .
Anyway if it pass your EDD to long your gynea will advise you on it.
No wori, enjoy the period when she is still in your tummy coz later you might miss these days.