Muscle contracts in response to stretch, which is why you get cramps as your uterus expands. It's quite normal, unless it starts to come and go in regular intervals, in which case, you should call your doctor or go to the hospital. Braxton Hicks contractions can generally be stopped by resting and getting hydrated. Have a glass of water (your uterus can also contract if your water level gets too low), and lie down on your left side for awhile.
at 4:15 PM on Dec. 27, 2009