I don't know what it would be best to be tested for with your history, but I know other ladies have asked for a thrombophilia panel to check for blood clotting disorders. I also asked for an ANA test but I have a family history of autoimmune disorders.
I would definitely ask for a thyroid test, if you haven't been screened for thyroid problems already. The Endocrine Society and American Association of Clinical Endocrinologists recommend thyroid screening for anyone with a history of pre-term labor or miscarriage. http://www.preeclampsia.org/forum/viewt ... id#p350105
. Most docs will screen via a TSH test (Thyroid Stimulating Hormone) but in your shoes I would want a full thyroid panel run including testing for anti-thyroid antibodies. Since positive antibody levels- even with a normal TSH- have also been linked to increased risk of miscarriage.
I hope this helps, good luck!