To anyone who has used a fetal heart doppler?

You need to get an expensive one for it to work. I bought one from the store in town, it didn't work at all!! Don't waste the money. Honestly, once you feel baby move you always can tell if they are okay without needing to hear the heartbeat. I know it is more comforting to hear it but really, unless you want to spend a ton of money, most of the cheap ones are just a disappointment.