Heartbeat

can a transvaginal ultrasound pick up the mothers heart beat as well? or an abdominal ultrasound? I went to the hospital the other night and a trainee was doing my u/s and she said my baby’s heart beat went from 160 to 80 but when the nurses checked me mine was 80. The doctor had said it could’ve been possible she just picked up my heartbeat instead but has anyone else heard of this?