This app couldnt even find my heartbeat, much less my babys at 15 weeks. Actually, you can hold the phone up in the air and it still says the calculated heartbeat is 150. It would be awesome if it worked, but it doesnt. Its a good things its free. If you use it and cant find your babys heartbeat, dont let it worry you. Its just the app.
Drumma girl about Baby's heartbeat Free, v1.0