Fetal heart monitoring measures the heart rate and rhythm of your baby (fetus). This lets your doctor see how your baby is doing.

Your doctor may do fetal heart monitoring during late pregnancy and labor. The average fetal heart rate is between 110 and 160 beats per minute. It can vary by 5 to 25 beats per minute. The fetal heart rate may change as your baby responds to conditions in your uterus. An abnormal fetal heart rate may mean that your baby isn't getting enough oxygen or that there are other problems.

There are two ways to do fetal heart monitoring: external and internal.

This method uses a device to listen to and record your baby's heartbeat through your belly (abdomen). One type of monitor is a Doppler ultrasound device. It's often used during prenatal visits to count the baby's heart rate. It may also be used to check the fetal heart rate during labor. The doctor may also check your baby's heart rate continuously during labor and birth. To do this, the ultrasound probe (transducer) is held on your belly with a soft belt. A separate monitor may be placed to monitor contractions. It sends the sounds of your baby's heart to a computer. The rate and pattern of your baby's heart rate are shown on a screen and may be printed on paper.

This method uses a thin wire (electrode) put on your baby's scalp. The wire runs from the baby through your cervix. It's connected to the monitor. This method gives better readings because things like movement don't affect it. But it can be done only if the fluid-filled sac that surrounds the baby during pregnancy (amniotic sac) has broken and the cervix is opened. Your doctor may use internal monitoring when external monitoring isn't giving a good reading. Or your doctor may use this method to watch your baby more closely during labor.

During labor, your doctor will watch your uterine contractions and your baby's heart rate. Your doctor will note how often you're having contractions and how long each lasts. Because the fetal heart rate and contractions are recorded at the same time, these results can be looked at together and compared.

Your doctor may check the pressure inside your uterus while doing internal fetal heart monitoring. To do this, they will put a thin tube (catheter) through your cervix and into your uterus. The catheter will send uterine pressure readings to a monitor.

Fetal heart monitoring is especially helpful if you have a high-risk pregnancy. For example, your pregnancy is high risk if you have diabetes or high blood pressure. It's also high risk if your baby isn't developing or growing as it should.

Fetal heart monitoring may be used to check how preterm labor medicines are affecting your baby. These medicines are used to help keep labor from starting too early.

Fetal heart monitoring may be used in other tests, including:

• Nonstress test. This measures the fetal heart rate as your baby moves.
• Contraction stress test. This measures fetal heart rate along with uterine contractions. Contractions are started with medicine or other methods.
• Biophysical profile. This test combines a nonstress test with ultrasound.

Things that may affect the fetal heart rate during labor:

• Uterine contractions
• Pain medicines or anesthesia given to you during labor
• Tests done during labor
• Pushing during the second stage of labor

Your doctor may have other reasons to use fetal heart monitoring.

Radiation isn't used for this test. The transducer usually causes no discomfort.

You may find the elastic belts that hold the transducers in place slightly uncomfortable. These can be readjusted as needed.

You must lie still during some types of fetal heart rate monitoring. You may need to stay in bed during labor.

With internal monitoring, you may have some slight discomfort when the electrode is put in your uterus.

Risks of internal monitoring include infection and bruising of your baby's scalp or other body part.

Note: Internal fetal heart rate monitoring is usually avoided in some type of maternal infections such as HIV or hepatitis. This is because you may pass the infection on to your baby.

You may have other risks depending on your specific health condition. Be sure to talk with your doctor about any concerns you have before the procedure.

Certain things may make the results of fetal heart monitoring less accurate. These include:

• Your body size.
• Your position or the position of the baby.
• Too much amniotic fluid (polyhydramnios).
• Your cervix isn't dilated, or the amniotic sac isn't broken. Both of these need to happen to do internal monitoring.

• Your doctor will explain the procedure to you. Ask them any questions you have about the procedure.
• You may be asked to sign a consent form that gives permission to do the procedure. Read the form carefully and ask questions if anything is not clear.
• The consent form for fetal heart monitoring may be included as part of the general consent for labor and birth.
• Tell your doctor if you are sensitive to or are allergic to any medicines, latex, tape, or anesthesia.
• If fetal heart rate monitoring is done along with another monitoring test, you may be asked to eat a meal before the test. This can help make your baby more active.
• The amniotic sac must be broken and your cervix must be dilated several centimeters before the internal device can be put in place.
• Follow any other instructions your doctor gives you to get ready.

You may have fetal heart monitoring in your doctor's office or as part of a hospital stay. The way the test is done may vary depending on your condition and your doctor's practices.

Generally, fetal heart monitoring follows this process:

1. Depending on the type of procedure, you may be asked to undress from the waist down. Or you may need to remove all of your clothes and wear a hospital gown.
2. You'll lie on your back on an exam table.
3. The doctor will put a clear gel on your abdomen.
4. The doctor will press the transducer against your skin. The doctor will move it around until they find the fetal heartbeat. You'll be able to hear the sound of the fetal heart rate with Doppler or an electronic monitor.
5. During labor, the doctor may check the fetal heart rate at intervals or nonstop, based on your condition and the condition of your baby.
6. For continuous electronic monitoring, the doctor will connect the transducer to the monitor with a cable. A wide elastic belt will be put around you to hold the transducer in place.
7. The doctor will record the fetal heart rate. With continuous monitoring, the fetal heart pattern will be displayed on a computer screen and can be printed on paper.
8. Once the procedure is done, the doctor will wipe off the gel.

1. You'll be asked to remove your clothes and put on a hospital gown.
2. You'll lie on a labor bed. Your feet and legs will be supported as for a pelvic exam.
3. Your health care provider will do a vaginal exam with a gloved hand to see how far you're dilated. This may be slightly uncomfortable.
4. If the amniotic sac is still intact, your provider may break open the membranes with a tool. You will feel warm fluid coming out of your vagina.
5. Your health care provider will feel the part of the baby at the cervical opening with gloved fingers. This is usually the baby's head.
6. The provider will put a thin tube (catheter) into your vagina. They will put a small wire at the end of the catheter on the baby's scalp. The provider will gently turn it on the baby's skin.
7. The provider will remove the catheter and leave the wire in place on the baby's scalp.
8. The provider will connect the wire to a monitor cable. They will keep it in place with a band around your thigh.
9. You may not be able to get out of bed with nonstop internal fetal heart rate monitoring.
10. Once the baby is born, the provider will remove the wire.

You don't need any special care after external fetal heart monitoring. You may go back to your normal diet and activity unless your doctor tells you otherwise.

After internal fetal heart monitoring, your health care will check your baby's scalp for infection, bruising, or a cut. The provider will clean the site with an antiseptic.

Your doctor may give you other instructions, based on your situation.

Before you agree to the test or procedure, make sure you know:

• The name of the test or procedure.
• The reason you are having the test or procedure.
• What results to expect and what they mean.
• The risks and benefits of the test or procedure.
• What the possible side effects or complications are.
• When and where you are to have the test or procedure.
• Who will do the test or procedure and what that person's qualifications are.
• What would happen if you did not have the test or procedure.
• Any alternative tests or procedures to think about.
• When and how you will get the results.
• Who to call after the test or procedure if you have questions or problems.
• How much you will have to pay for the test or procedure.