This is my second pregnancy, I had only a few bh in the last couple of weeks of my first pregnancy and they werent really painful. I am now 18 weeks, and have been getting really sharp crampy pains over the last 3 days... kinda like a stitch but sharper... lasts about 30 seconds. Isnt it a bit early for bh? Not really sure what one is!! I have a low lying placenta and have had bleeding as a result, could it be related to this rather than a bh?