If you haven't already - I would consider a workup for Recurrent Pregnancy Loss (RPL).
This includes bloodwork to rule out immunlogic (antibodies) and/or thrombolitic (blood clotting disorders) issues. A step further might be a chromosome compatibility panel for both you and DH. Here are a couple of links:
I'm truly sorry for your losses - and I admire your perserverance.
01/03, 04/04, 12/04