When do Braxton hicks start??

[first_time_mummy]

HI,

I havent even had one yet so Ill probably think Im in labour if I get any.....

Im 38 weeks tomorrow, and havent yet experienced any either.
This is my first baby. and I have only really felt mild period like cramps, and a heavy feeling in my abdomen. but im pretty sure these arent braxton hicks?? Im not sure...what exactly do they feel like?

[KatieRabbit]

I have read you feel them from 20 weeks. I have had them this time around for weeks now but none at all first preg!

[Party-of-five]

first_time_mummy i would describe them as a tightening feeling...like tightening up a belt around your tummy. thats the best i can do sorry