What's the possibility....

I went to my first prenatal visit not too long ago and everything came back good. The heartbeat was 185bpm and measuring at a good rate. I wanted to know if there was a possibility that the baby won't have a heartbeat? I'm asking because of heard of some women who were fine and then went for there next appointment and the baby no longer had a heartbeat. I miscarried in the past so it's always in back of my head. Any advice is greatly appreciated.