Yes it is possible but statistically most misscarriages are in the first trimester which your out of !!! why are you worried are you spotting??
Thats right Why u think something is wrong? At this time, after 12 weeks its not that common to have m/c, specialy if everything was OK on your doc visit. Did u have u/s? The first sign something can be wrong is if the baby is much smaller then should be- so if you are 12 weeks baby mesure for 10 weeks let say. If you didnt have u/s or you dont have any signs of miscarriege dont worry, be positive, baby can feel this, you need to stay happy so baby can be happy. If you worry that you dont have pregnancy 'sign' anymore this is just the time you will start feeling good again and most symptoms will go away.
What makes you think something is wrong? Try not to worry unless you are told something is not right.