Doppler arrived

[honeyloops]

could be your own heartbeat ur picking up / placenta. Once you find it count it for 15seconds, I normally have a count of 39 beats which works out at 156bmp. Your own heartbeat will be much much slower, perhaps even half that speed.
hth

 

[Rósa]

The placenta has a HB? Im worrying now that Im not actually hearing the hb

 

[honeyloops]

same rhythm as your own heartbeat, but the sound of the blood going through the placenta.

This link may help you futher
http://www.fetaldopplerfacts.org/facts/dopplers/fetal-heartbeat-doppler-sounds.php