Pregnancy, along with PMS, ovulation, and unhealthy eating can all cause bloating. First, try to rule out a food cause. Have you been eating more unhealthy (fried, fattening, extra protein) the last few days? Have your bowel movements been abnormal (i.e., are you constipated- though, this can happen with pregnancy as well)? Have you been experiencing any cramping or gas pains?

If not, it may be due to something else. If you are about to start your menstrual period, this too can cause bloating. If your menstrual period does not begin within a few days of when you expect it, it may be time to take a pregnancy test.