Then again, this answer might help you...
You can hear a baby's heart beat usually at about 12 weeks when doing an ultrasound, providing you don't have an extra layer of fat above the pubic bone. The position of the placenta might be a little draw back also or the way the baby is laying in the uterus. When using a Stethoscope you would have to wait till 20 weeks.
kermit0504, Answers Expert