I have had 4 miscarriages in a row in the past year...? I am 34.  I had my first son when I was 19, he is 15 now.  I had a miscarriage 4 years ago.  3 years ago I was diagnosed with diabetes...and I am well controlled.  I got pregnant 3 months after my diagnosis and delivered a healthy baby boy who is now 20 months old.
I have had 4 miscarriages in the past year.  As soon as I miss my period and get a positive test...hours later I miscarry.  It is horrible.  Can anyone tell me what in the world might be going on?  My progesterone was 13 this time and my doctor said she likes to see it at 20.  So I was on the suppsitories for a week and I did not bleed and was so happy.  Then I went to have my blood drawn and my HCG did not double not one time.
Last year I had to have methotrexate because the baby would not fully come out.  I really need some answers...it just doesn't make sense.

Summarized question: What could cause recurrent miscarriages in a 34-year-old?