dull menstrual- like pains? 23 weeks pregnant

hey girls, so i'm 23 weeks +2 pregnant and i sometimes feel this dull ache under my tummy, kinda like period cramps, but mild and brief. is this normal or is it something i should be concerned about?

thanks 

My Dr says those are just braxton hicks. Totally normal.

I had those too. I was worried so I asked my OB. He said it was just stretching of the uterus and as long as there is no bleeding everything will be fine. He said mine were a little more severe because of the scar tissue from a laproscopy surgery I had months earlier.