Fetal Heart Rate Monitoring

What is fetal heart rate monitoring?

Fetal heart rate monitoring is a common test that healthcare providers use during pregnancy and labor. It measures your baby’s heart rate, which is a sign of how well your baby is doing.

Why is fetal heart rate monitoring done?

Fetal monitoring tracks the speed and pattern of your baby’s heartbeat. The average heart rate of a developing fetus is 110 to 160 beats per minute.

By monitoring your baby’s heart rate, your provider can tell if the heart rate is too high or low or changing too much. Moderate fluctuations between six and 25 beats per minute over a 10-minute period are normal.

Irregularities in the heart rate could mean your baby is not getting enough oxygen or has other problems. If your provider sees this, you may need other testing or emergency delivery.

When is it done?

Situations in which your provider may use fetal monitoring include:

• Prenatal visits: Your healthcare provider may check your baby’s heart rate at routine prenatal care appointments.
• High-risk pregnancies: Monitoring is more likely if your pregnancy is high risk. Conditions that may put you at higher risk of problems during your pregnancy include preeclampsia, diabetes or bleeding during pregnancy.
• Birth of your baby: Your provider will monitor your baby during labor and delivery.

What are the types of fetal heart rate monitoring?

The types of fetal heart rate monitoring are:

External monitoring

External monitoring occurs on the outside of your abdomen. Your provider may do this using these manual or electronic devices:

• Fetoscope: This instrument is similar to a stethoscope your provider uses to listen to your heart and lungs. Its end is cone-shaped. Your provider presses the cone to your belly to listen to your baby’s heartbeat.
• Handheld Doppler ultrasound: Doppler ultrasound uses sound waves to measure your baby’s heart rate. Providers often use handheld Doppler devices during prenatal visits. Your provider will squeeze gel onto your abdomen and place the probe in the gel. The device picks up your baby’s heartbeat and displays the readout on a screen. You can purchase versions of handheld Doppler devices for at-home use. However, the Food and Drug Administration (FDA) does not support the use of these devices at home.
• Continuous Doppler ultrasound: During labor and delivery, your provider may opt for continuous electronic fetal monitoring. They’ll hold the ultrasound device in place on your belly with an elastic strap. A second strap holds an instrument that measures your contractions. Wires from the instruments attach to a monitor that provides a continuous readout of your baby’s heart rate.

Internal monitoring

Less often, providers monitor your baby inside your uterus. Your provider attaches a wire to your baby’s head to continuously track the heart rate. Providers use internal monitoring during labor and delivery only after your water has broken and when:

• External electronic fetal monitoring results are unreliable.
• You need more precise monitoring.

What are the risks of fetal heart rate monitoring?

In general, fetal heart rate monitoring is safe. But most experts believe that continuous monitoring isn’t necessary for pregnancies at low risk of complications.

Continuous electronic fetal monitoring can restrict your movement, which can be helpful during labor. It also increases the risk of an unnecessary cesarean section or delivery using a vacuum device or forceps.

Internal monitoring can increase the risk of:

• Injury to your baby’s scalp and asphyxiation of your baby.
• Maternal infection.
• Transmission of HIV or genital herpes from mom to baby.

Are at-home fetal heart rate monitors safe?

Handheld Doppler fetal heart rate monitors are widely sold for at-home use. Compared with professional devices that provide detailed information about heart function, at-home models only measure heart rate.

Ultrasounds are safe if performed when they are medically necessary and by trained professionals. But under some circumstances, ultrasound technology can heat tissues and produce small bubbles in tissues. The FDA discourages the use of these devices because they:

• Are not medically necessary.
• Lack controls on how often or how long people will use the device.
• Require training to accurately use the device and interpret the readings.
• May produce inaccurate results that can lead to undue stress or a false sense of confidence.

Are at-home fetal heart rate apps safe?

Mobile apps are also available for fetal heart rate monitoring. Some require the purchase of an accessory Doppler device. Others claim to use the built-in microphone on your mobile device to detect your baby’s heart rate.

A study of 22 apps that did not require a separate accessory found that none could detect the fetal heartbeat. Also, many apps provided false information in the description or failed to add a medical disclaimer.

Instead of fetal heart rate apps, a better way to monitor your baby is to track their movement. You should start to feel your baby move between 16 and 20 weeks of pregnancy. Talk to your provider about using this method to check on your baby’s well-being.

When should I know the results of the test?

Your provider should let you know how your baby is doing right away.

What if fetal heart rate monitoring shows a problem?

An abnormal heart rate or rhythm does not always mean your baby is in danger. Your provider may continue to monitor your baby or order other tests.

Changes in your baby’s heart rate that last 10 minutes or more are a concern. If this happens, your provider will consider immediate cesarean section or vaginal delivery using a vacuum device or forceps.

A note from Cleveland Clinic

Heart rate monitoring can give your healthcare provider valuable information about how your baby is doing, but you may not benefit from all types of fetal heart rate monitoring. At-home devices and mobile apps are not recommended. People with low-risk pregnancies do not need continuous electronic fetal monitoring during labor. Talk with your provider about the risks associated with these types of monitoring. This will help you decide what is best for you and your baby.