Fetal heart rate monitoring (FHR)

Fetal heart rate monitoring (FHR) is a process that allows your doctor to see how fast your baby's heart is beating. If you are pregnant, your doctor will want to make sure your baby is healthy and growing well. One way to do this is to check your child's heart rate and rhythm.

The doctor will most likely do this later in pregnancy and during labor. They may combine it with other tests to investigate further if you have diabetes, high blood pressure, or any other condition that could cause problems for you and your baby.

Reasons to monitor FHR

A doctor is more likely to use FHR monitoring when your pregnancy is at high risk. FHR monitoring may be required in the following cases:

You have diabetes.
You have high blood pressure.
You’re taking medicine for preterm labor.
Your baby isn’t growing or developing normally.

The doctor may also use FHR monitoring to make sure the baby is okay when you give birth or if there are other reasons to check your baby's heart rate.

Types of FHR monitoring

The doctor can monitor your child's heart rate in several ways. They can listen to or electronically record rhythms outside of your belly. Or, once your water breaks and you're in labor, they may thread a thin wire through your cervix and tie it to your baby's head.

External monitoring: If your pregnancy is going well, your doctor will likely check your baby's heartbeat from time to time using a special stethoscope or a hand-held device called Doppler ultrasound. Doctors sometimes refer to this type of FHR monitoring as auscultation.

If you need it, your doctor may do a special test called a non-stress test, usually starting around the 32nd week of your pregnancy. It counts the number of times your baby's heart beats over a 20-minute period.

For the test, you lie down with an electronic sensor belt around your abdomen that continuously records the baby's heartbeat.

The doctor may also wrap a belt with an electronic sensor around you to measure the baby's heart rate during labor. This lets them know if contractions are stressing your baby. If so, you may need to give birth as soon as possible.

Internal Monitoring: Once the water has broken and the cervix has opened to prepare you for childbirth, the doctor may insert a wire called an electrode through the cervix into the uterus. The leash is attached to the child's head and connected to the monitor. This gives a better reading than listening to your baby's heartbeat outside.

Risks of FHR monitoring

External monitoring is not dangerous. It won't hurt or use radiation. If your doctor uses a belt, this may be a little uncomfortable. It may also mean that you have to stay in bed during labor.

Internal oversight risks include:

Slight discomfort
Infection
Bruising or scratching your baby’s scalp

If you are HIV positive, you should not have internal FHR monitoring. This is because there is a risk of passing the infection to your baby. If you have other health concerns, ask your doctor about any special risks.

FHR monitoring procedure

FHR monitoring can be done in a doctor's office or in a hospital. The procedure will depend on the type of monitoring you will have.

External FHR monitoring procedure

Your doctor will ask you to undress and lie down on an examination table or work bed.
You will have a clear gel on your stomach.
Your doctor will press a device called a Doppler transducer on your abdomen and move it around.
You will hear the sound of your baby's heartbeat.
If your doctor wants to continuously measure your heart rate, they will use a wide belt to hold the sensor in place.
Your doctor will record the FHR. You can see it on the computer screen.

Internal FHR monitoring procedure

You will be asked to undress and lie down.

You’ll be asked to undress and lie down.
You’ll put your feet and legs in supports, like you’re getting a vaginal exam.
The doctor will check to see if your cervix is dilated.
If your water hasn’t broken, the doctor may break it.
The doctor will feel for your baby’s head.
The doctor will put a thin tube (catheter) with a small wire at the end into your vagina.
The doctor will put the wire on your baby’s scalp and remove the catheter.

Once connected to the cable, the wire will record your baby's heartbeat until the doctor removes it or your baby is born.

FHR monitoring results

A healthy baby's heart normally beats 110 to 160 times per minute in the womb. It speeds up when the baby moves. Signs of possible problems include:

Heart beats slower than 110 beats a minute
Heart beats faster than 160 beats a minute
A heartbeat pattern that isn’t normal
The heartbeat doesn’t go up when the baby moves or during contractions

The absence of a normal heartbeat doesn't always mean something is wrong with your baby. But it could be a sign that the baby isn't getting enough oxygen.

Your results may also be less accurate if:

You’re obese.
You or your baby is in the wrong position.
You have too much amniotic fluid.

Treatment of abnormal FHR

If your baby's heartbeat is not what it should be, the doctor may try:

Changing your positions to move the baby
Giving you fluids through an intravenous
Having you breathe extra oxygen
Relaxing your uterus with medicine to slow contractions
Giving you other drugs

If these steps don't bring your baby's heart rate back to normal, you may have to deliver them right away. If the cervix is completely open, the doctor may use a tool called forceps or a special vacuum to help push the baby out. Otherwise, you will have a baby by caesarean section.