Symptoms of Miscarriage
If you are pregnant, it is important that you be able to identify the signs of a miscarriage. If you think that you are having a miscarriage, contact your health care provider or local hospital right away. Symptoms of a miscarriage include:

* vaginal bleeding that doesn't stop within a few days
* abdominal cramping
* lower backache
* heavy bleeding accompanied by blood clots or tissue

It is important to understand that many pregnant women experience slight bleeding during their pregnancies. Bleeding is often a normal occurrence and doesn't always signal a miscarriage. To be on the safe side though, inform your health care provider of any type of vaginal bleeding during your pregnancy.

To add to this, one may also feel numbness or weakening of the thighs and knees and the legs as an early warning sign for miscarriage. Thanks much for this info tho! Most helpful!

Very common symptom is bleeding sometimes with clots and may have abdominal pain. Some doctors may find the miscarriage if go for ultrasound test. Diabetics person have more chance for miscarriage

You are right when you say that some spotting / light bleeding is normal and harmless during pregnancy. It is when bleeding persists and is accompanied with pain that the woman should worry.

I was not aware about numbness, so thanks for posting it bammer!