The same thing happened to me. Normal karyotype. The blood work showed I have MTHFR, a clotting disorder. If one of your levels in the panel was high, it sounds as though that was the reason. Clotting disorders are genetic issues; so it is nothing you did, or could have prevented. They will need to start treating the clotting disorder.
For me, I am now on a special prenatal vitamin, especially for MTHFR, and I will be put on heparin during my next IVF/pregnancy. At least you can treat the problem now that it's been identified. Good luck with your appt. The hematologist will probably put you on blood thinners, which can make all the difference.