I agree with the other girls, get betas done to be on the safe side. HCG levels should fall fairly rapidly, but of course it depends on what your numbers were when you miscarried. Although I was 10 weeks pregnant when I MC, I had lowish numbers and I got a BFN within 2 weeks. The EPAU I went to said to contact them if I didn't get a BFN after 2 weeks, and they would do another ultrasound to make sure I had MC fully. AF arrived 5 weeks after the MC. Good luck x x