Thanks ladies! I'm trying not to get to worried. I brought it to put my mind at rest!! Lol
I have one, can't remember exactly when I started using it, 18 weeks maybe? Give it more time and be patient, I loved using mine I'm 35 weeks now it still picks up heartbeat but it's harder as he moves around too much lol.
Sometimes 10 wks is just too early to hear it. Give it a try another time and try not to worry about it if you can't hear it. Not only is it hard to find because baby is so small they also move around alot!