Yes, a doctor would be able to tell you had had a miscarriage. Even if you had not yet noticed you were pregnant, a doctor still would be able to note the signs of a miscarriage. If you didnt even know you were pregnant, a miscarriage that early on probably just seemed like a heavier/more cramp-filled period. Doctors are often able to tell if a miscarriage did in fact occur if no pregnancy is present, but there is still small deposits of HCG in a blood test (the pregnancy hormone, which takes the body a little while to flush itself of after a miscarriage).