i don't think that a miscarriage is what your after, possibly abortion? or have you had a miscarriage and you haven't seen a doctor yet? if this is the case you should really make an appointment with your local GP. OK but what happens if you don't see the doctor about it
The period can be late without you having a miscarriage. It happens from now and then. If you had a miscarriage the test will show positive for a little while longer since it takes time for the hormones to settle.
If you are talking a natural miscarriage that usually occurs in the first trimester it usually happens because there's something wrong with the fetus. If you are talking about abortion you have to go to a clinic.