but, I would contact your doctor just in case. I can tell you that some women do bleed during their pregnancy but since you have already had one miscarriage
I'm sorry for your miscarriage, I know how it can make your next pregnancy quite worrisome. Many women have spotting though and go on to have successful pregnancies. It does not mean you are miscarrying for sure.
However, I would call your doctor right away and see if you need to go in. If it is heavy, red or persistent, he/she may be concerned.