I am pregnant with my sixth baby and started feeling tightenings at around 18 weeks. They have much more intense as my pregnancy have progressed and are now getting painful. I am 30+ weeks now. All good prep ;)
I started feeling them since the beginning of my pregnancy I am now 32 weeks and they are startingto get more intense.
I only got them once about 2 weeks before I went into real labor. That was around 36 weeks.
I started feeling them around 34 weeks. They became constant at around 36 weeks