I have a doppler and around 8 weeks 5 days, the heartbeat went up a lot! In the 9th week, the heartbeat was always around 178-186 and even up to 190 sometimes! I was honestly sort of worrying. Baby now has a steady 154-164 heart rate that jumps up to around 172 sometimes but that is when baby is very active as I can hear kicks on doppler now. At our NT scan, the heart rate was 157 and baby was wiggling around. So just remember that heart beat peaks at 9 weeks and then starts to level out by 12 weeks.