The Fetal Doppler uses ultrasound technology to bounce sound waves off the baby and return a representation of the fetal heart beat. Some specialized devices can be used as early as eight weeks. Though 12 weeks into pregnancy is a more normal time frame. The sound is usually that of galloping horses. (You can hear a baby's heart beat via doppler here.)
This device can be used by doctors or midwives. Hillinton sells fetal doppler for women in pregnancy for home use.
