Slowly raising Beta HCG level.

Patient: Hi Doctor, My name is Shilpa. I had a miscarriage in January 2011. Now i’m conceived and i did beta hcg test on 20th august 2011, its saying 610ml. My last period was on 20th July 2011. Now the second beta HCG test done on 27th August 2011, in that it was 1900ml. Is there any strange in this report. My Dr prescribed me Folic acid, Duphaston, Aspirin, Dimet500,Euthyrox25 alternate and Prolution Depot500mg. Also done Ultrasound but nothing was visible in that. My Dr said the beta HCG should double every 48 hours. I’m afraid whether this pregnancy will also be miscarried. Kindly advice me the possible solution to increase beta HCG and to protect pregnancy. Awaiting for your kind reply. Regards Shilpa.