The "average" range is 140 to 170bpm, so 171bpm sounds perfectly fine to me. If you're worried, talk to your doctor. I've had 176bpm in the past and it was deemed perfect.
My babies heart rate at 8.2 was 191!! I was terrified but the doctor wasn’t concerned. I was sure something was wrong. It came down to low 170s at 10 weeks and then 150s by 14 weeks.
Re: Heartbeat rate 8 weeks