Does History Of Abortions Cause Miscarriages?

hello dr.
i am trying to concieve from 3 to 6 months bt not able to concieve.
by d & c i aborted my first pregnancy. second pregnancy aborted by medicine. i aborted both due to finanacial problems. bt now m better.so i concived twice bt both end up into misscarage of 5 weeks.bt now m again trying to concieve from october2010.bt not able. plz suggest me what is happining with me.

plz reply me at YYYY@YYYY