2nd miscarriage- do you know the cause of your miscarriages?

Wendy
I turned 13 weeks today and also found out that the heart has stopped beating. I just miscarried with my first pregnancy 5 months ago. Since this is my second, they will send the baby off for chromosomal testing and they will also test me for auto immune and blood clotting disorders. I was taking progesterone suppositories so that shouldn't be the cause. Has anyone else been through all this testing and actually found out the cause of the miscarriages?