Awesome responses, thank you mama's! I now have a much better idea of what to expect!
I just had my baby so I remember it well. For me they started as mild cramping through the night. My water broke in the morning and contractions were tolerable up until a certain point. When you hit that point... You know, the "give me the epidural!!!" point.
So for me they built up in intensity and my labor was 7 hours. Everyone's is different I suppose
Both my labors/contractions started feeling like bad diarrhea cramps. Then diarrhea plus bad period cramps. The first labor was just like bam, nonstop close together contractions. When i got to the hospital he was delivered in 2 hours. The second was a little slower, contractions werent as intense right off the bat, so i had time to download a labor timing app and sat there and timed them while i fixed my hair and put on some concealer lol. She was delivered 5 hours after I got to the hospital (I waited about an hour at home until they were 5 min apart).
Mine were gradual... In total I had a 18 hour labour. At first they came about every 15 minutes for an hour or 2, very low intensity (just felt like something between a strong Braxton hicks and a light poo cramp lol), then 10 minutes apart for another 5 hours or so, still very low intensity. Honestly, I can't really say they bothered me much until around 14 hours later then they really started to ramp up! Everyone is different obviously but that was my experience :)