What Causes Raised D-dimer Levels After A Miscarriage?

I 36 yrs of age and have had two successful pregnancy in 2007 and 2009. I have recently miscarried in Jan 2010 and May 2010. I have had some testing and all haas come back normal. However, my d-dimer levels came back raised. When the blood test was done, un beknow to me or my doctor I still had retained products of conception left over from the curette. Would this cause this elevation in d- dimer. I have since had another curette to clear out the products. Should I have another blood test to check d-dimer levela before I try again.