Hi i'm currently 11 weeks pregnant , baby's hr at 8 week scan was 172bpm and growing well, what % is risk of miscarriage at this point?

About 5 % or less: Factors which influence risk of early spontaneous miscarriage are maternal age, previous history of early miscarriage, and smoking history. As you are not of advanced maternal age (>35), and have a previously established normal pregnancy at 8 wks by ultrasound, your risk of miscarriage is 5% or less, better if you are NOT a smoker