- Women's Health
How to Calculate Fetal Heart Rate With Doppler During Pregnancy: Tracking the Tiny Heartbeat
The tiny heartbeat of a fetus is hard to hear. At the doctor's office, you can hear your baby's heartbeat on doppler, with a stethoscope or a fetoscope. But even at home, as early as 8 weeks into your pregnancy you can use a handheld home fetal doppler monitor to count your baby's heartbeats using ultrasound technology. Many parents like to listen to the fetal heartbeat before they ever listen to it at the doctor's. Then you can calculate the fetal heart rate using a simple formula. Follow these easy, step-by-step instructions for how to calculate your unborn baby's heartrate.
Check the Fetal Heartbeat
First, check with your doctor or nurse midwife to make sure using a fetal doppler at home is advisable for you. Generally, they are considered safe if used occasionally--though I personally would not use it every day unless specifically medically advised to do so.
You can rent or buy a home fetal doppler monitoring machine. You'll also need a stopwatch or a clock with a second hand, and some ultrasound gel.
Lying in a comfortable resting position, rub the ultrasound gel on your abdomen where the baby's heart is likely to be. That location changes throughout your pregnancy.
Holding it in one hand, set the doppler probe face down on the area with the gel near your navel. Turn on the doppler monitor and turn up the volume. Slowly move the doppler probe downward and around--slow being the key word here. When you hear something, adjust the volume to get a clear sound. You'll hear a galloping heartbeat rhythm that will sound quite fast. That's your baby. (Don't be fooled by your own heartbeat, which is much slower.)
Calculate Fetal Heart Rate
Check the stopwatch or second hand on the clock. Count the heartbeats you hear for 20 seconds. For example, you may hear 45 heartbeats.
Now, triple that number you just counted--that is, multiply it by three. So in this example, 45 times 3 equals 135. You've just calculated the fetal heartrate. 135 is the BPM (beats per minute).
The normal heartrate for a fetus ranges from 120 to 160 beats per minute and varies from 5 to 25 beats from this, particularly when your baby is moving or asleep. Check with your doctor if you have any questions or concerns.