No 'pre-labour' prior to birth date with #1 - but then he was 18 hours, the first 10hours was what would be considered "pre-labour".
DD I had 4 or 5 round of 6-8 hours of contractions "pre-labour" and she was born in 2hr50m from first contraction.
FWIW my mum's third she has "pre-labour" for weeks and my brother was born 38mins from waters breaking.