Have you been tested for antiphospholipid syndrome? It's a clotting disorder that can lead to multiple miscarriages. It IS possible to carry a baby to term if you have it, you just need to take a low-molecular weight heparin (which is not harmful to the baby like Coumadin is), and maybe baby aspirin.
You can find more information
here . Feel free to PM me about it, as I have APS (as you might have guessed). It can be dx'd by a couple of blood tests.
Candy