It seems I had then only for 1 week, week 30, and thats it
Mine started around 20 weeks as well. At first they would just be noticeable, then the pain would make me sit up straight and try to brace myself, now I'm about ready to scream out. Im 34+4 weeks. But they only last for no longer than 1 minute for me.
I started getting braxton hicks at around 20 weeks and im still getting them now and im 36+4 weeks. They usually last under 1 minute each time but can happen atleast 10 times per day if not more. They are getting worse now along with a hot flush each time. I expect everyone would be diffrent though :)