I think there’s two types, I’ve had a Doppler where they just listen to the heart beat and this was done by midwives. The 2nd was also referred to as a Doppler scan and was an appointment booked in with a sonographer, where it’s essentially the same as the usual ultrasound scans but they just measure the fluid around baby and how well the placenta / cord is working. The main difference between this and a normal ultrasound is they don’t measure baby.
Doppler scan looks for blood flow in the placenta
Just listens to the baby’s heart beat. X