What are your thoughts on ultrasounds and doppler use?

I am going for my 5th ultrasound on Saturday, which will be my anatomy scan. I had a subchorionic hemorrhage early on in my pregnancy that my doctor wanted to monitor. I also have an at home doppler that I definitely do not use every day, but have used frequently enough. Just wondering what everyone’s thoughts are on dopplers and ultrasounds. My doctor says they are safe but I have heard lots of conflicting opinions.