6 weeks heartbeat ok?

So I went in today for my first prenatal appt. I am 6 weeks 1 day today and the nurse saw the flickering of the heartbeat so she played turned on the doppler in a transvaginal ultrasound. She had a but trouble hearing so she kept turning the doppler on and off about 3 times. Isnt using it a little dangerous for the baby to be listening to their heartbeat that early and have it being turned on 3 times to get the heart rate. Measured at 118 bpm. It wont harm the baby will it? I've had 2 prior miscarriages and I just want to make sure I bring this baby home this time... thank you.