Your doctor or midwife monitors the fetal heart rate of your baby to assess their well-being and how well they are tolerating labor. They primarily use electronic fetal monitoring (EFM), which is the most common obstetric procedure during labor. Your care provider uses EFM to recognize signs of low oxygen and respond quickly if your baby needs an intervention. While electronic fetal monitoring can identify emergencies, research shows that continuous monitoring does not necessarily improve outcomes and is linked to higher rates of cesarean and assisted births.

Most low-risk pregnancies can safely use intermittent monitoring. Hospital policies, provider training, and individual risk factors all influence the type of monitoring your provider recommends. By learning about your options and discussing them ahead of time, you and your care provider can create a plan that keeps your baby safe while supporting the birth experience you want.

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What is Electronic Fetal Monitoring?

From your care provider’s standpoint, monitoring your baby’s heart rate is the best way to track your baby’s well-being during labor and alert your doctor or midwife if there is a problem. Electronic fetal monitoring (EFM) is a method to continuously record your baby’s heartbeat and your contractions during labor. It uses sensors placed on your abdomen (or sometimes a small electrode placed on your baby’s scalp) to measure and record both the fetal heart rate and the timing and strength of contractions. The information appears as a graph on a screen or a paper printout that shows how your baby’s heart rate responds to contractions over time. This helps your care provider assess how your baby is tolerating labor and alerts them to any signs of distress.

According to ACOG, electronic fetal monitoring is the most common obstetric procedure in the United States. Nearly 90% of pregnant patients undergo EFM during labor. This procedure has a significant effect on decision-making, and 27.3% of primary cesarean deliveries are due to a nonreassuring fetal status as detected by EFM.

The problem with the practice of continuous electronic fetal monitoring is that there are still questions about whether this practice is evidence-based, even though it has become the standard of care in the United States.

Normal Heart Rate

Your baby’s normal heart rate baseline is typically between 110 and 160 beats per minute. Tachycardia heart rate higher than 160 beats per minute. Bradycardia is a rate lower than 110 beats per minute.

Your baby’s heart rate naturally fluctuates, and this normal variation is called variability or beat-to-beat variation. A healthy range of variability is usually 5 to 25 beats per minute. It’s also normal for your baby’s heart rate to speed up temporarily, known as an acceleration. These accelerations can happen when your baby moves, when your doctor or midwife presses on your belly to check their position, or if your provider touches your baby’s head during a vaginal exam. These short-term changes in heart rate are completely normal and a sign that your baby is doing well.

How Your Baby’s Heart Rate Changes During Labor

Labor and birth are the most physically demanding events of your baby’s life. Each time you have a contraction, blood flow to the placenta temporarily decreases, which briefly reduces your baby’s oxygen supply. While this might sound concerning, it is completely normal and part of how the body is designed to function during labor. The oxygen reduction is short, and your baby’s oxygen levels return to normal as soon as the contraction ends. When the oxygen supply to the placenta dips during a contraction, your baby’s heart rate naturally slows down. Once the contraction passes, their heart rate returns to its usual range. This pattern is normal, and your baby is well equipped to handle it.

Identifying Concerns and Understanding Fetal Distress

A doctor or midwife identifies fetal distress by looking for significant changes in a baby’s heart rate. Remember, your care provider monitors heart rate as a measure of your baby’s well-being. Before birth, babies rely on the umbilical cord and placenta to deliver oxygen. If a baby is not receiving enough oxygen in the womb, their heart rate may decrease. The goal of electronic fetal monitoring is to identify babies who are low on oxygen and determine the underlying cause to correct it.

The Risks of Low Oxygen

Metabolic acidemia occurs when a baby is deprived of adequate oxygen for over 60 minutes. This can increase the risk of complications after birth, including cerebral palsy. This condition is caused by abnormal brain development or damage to the developing brain that affects a child’s ability to control their muscles. About 85–90% of cases of cerebral palsy are congenital, meaning they occur before or during birth. Of all congenital cases, only about 6% are linked to birth complications that interrupt the oxygen supply. If you’re worried about your baby developing this condition due to reduced oxygen during birth, it’s important to know this is a rare complication.

Responding to Concerning Heart Rate Patterns

When fetal heart rate slows down (decelerates), care providers can take several measures to improve oxygen flow. This may include changing your position, giving you oxygen, adjusting or stopping medications like Pitocin, or relieving pressure on the umbilical cord. A fast heart rate (tachycardia) may indicate infection, hyperthyroidism, or placental abruption.

Monitoring your baby’s heart rate can also alert your care provider if an emergency arises and your baby needs to be born right away, utilizing a cesarean section or assisted vaginal birth. However, an abnormal heart rate pattern does not always indicate a serious problem. Before recommending a cesarean, your care team will attempt to determine the cause. In many cases, something as simple as changing your position can help restore oxygen flow to your baby.

Interpreting Results

The American College of Obstetricians and Gynecologists provides specific clinical guidelines that define what is considered normal for fetal heart rate patterns. These guidelines classify tracings into three categories.

• Category I (Normal): This pattern indicates that the baby’s heart rate is between 110 and 160 beats per minute with normal variability. There are no concerning decelerations, and early decelerations or accelerations may or may not be present. This pattern suggests the baby is well-oxygenated and tolerating labor normally.
• Category II (Indeterminate): This category includes everything that does not fit into Category I or III. It may include fast or slow heart rates, reduced or marked variability, or certain types of decelerations. These patterns are not clearly normal or abnormal and require closer observation or intervention to prevent progression to Category III.
• Category III (Abnormal): This pattern shows no variability and signs of distress, such as repeated late or variable decelerations, a consistently slow heart rate, or a sinusoidal (wave-like) pattern. Category III tracings suggest the baby may not be getting enough oxygen and usually require immediate action.

The three-tier system is not perfect. Researchers have proposed a five-tier, color-coded classification that provides more detail about levels of risk. A small study found the five-tier system identified fetal acidemia more accurately than the current system. In the future, a more refined classification system may be adopted so providers can better assess fetal heart rate patterns. ACOG acknowledges the limitations of the three-tier system for interpreting fetal heart rate tracings. They also emphasize the need for large, prospective studies on fetal heart rate assessment and management strategies to provide clearer guidance and improve the care of pregnant patients during labor.

Types of Fetal Heart Rate Monitoring

The method of monitoring your baby’s heart rate depends on your doctor or midwife, the policy of the hospital or birth center where you give birth, your risk of complications, and how your labor progresses. Your care provider will monitor your baby’s heart rate using one of two methods: auscultation or electronic fetal monitoring.

Auscultation

Auscultation means periodically listening to your baby’s heartbeat. Your care provider may use a Doppler transducer, a fetal stethoscope, or a Pinard horn, which is a trumpet-shaped device that amplifies sound. In most cases, a Doppler is used. This looks similar to a microphone, and when it is held against your belly, you can hear your baby’s heartbeat amplified through a speaker. You are likely familiar with this device as it is commonly used in prenatal appointments.

According to ACOG, there is minimal evidence to guide the optimal frequency for auscultation. The American College of Nurse-Midwives and the Association of Women’s Health, Obstetric and Neonatal Nurses recommend intermittent auscultation every 15–30 minutes during the active phase of the first stage of labor and every 5–15 minutes during the second stage, as long as both the fetal heart rate (FHR) and labor characteristics are normal. The frequency may vary, and ultimately, it is up to your care provider to decide how often they check your baby’s heart rate.

Electronic Fetal Monitoring

Electronic fetal monitoring uses instruments to continuously record your baby’s heartbeat and your uterine contractions during labor. The machine, called a cardiotocograph (CTG), provides an ongoing record. This allows your care provider to review how your baby’s heart rate and your contractions change over time. The results can appear as a printout or on a screen.

ACOG does not specify how often clinicians should review fetal heart rate tracings from an electronic monitor. They recommend that nurses or obstetric care clinicians review FHR tracings frequently. A member of the clinical care team should periodically document FHR tracing assessments at frequencies established per individual hospital protocols. It is important to note that every facility may have its own protocols and policies that will impact your care.

External and Internal Electronic Monitoring

Electronic fetal monitoring can be external, internal, or both. External monitoring involves two belts strapped around your abdomen. One belt uses a Doppler to detect your baby’s heart rate. The other measures the strength and timing of your contractions. This is the most common type of monitoring and is noninvasive. However, wires connect the belts to the CTG machine, which limits your ability to move around. If external monitoring is not producing a clear signal or your care provider needs a more precise reading, they may recommend internal monitoring.

This method involves placing a thin wire, called an electrode, on your baby’s scalp, as this should be the body part closest to your cervix. The electrode is secured in place with a tiny spiral wire to record your baby’s heart rate. Your provider can measure contractions using an intrauterine pressure catheter, which is a small tube that they insert through your vagina into your uterus. Internal monitoring only takes place after your water has broken and you are dilation is at least 1–3 centimeters. It may be recommended if you are carrying twins (to distinguish between baby A and baby B) or if you are significantly overweight, which can make it difficult to get an accurate signal externally.

Although internal monitoring is generally safe, it is not routine. It carries a small risk of infection and may cause minor bruising on your baby’s scalp. You might feel some discomfort when your provider places the electrode. Doctors will not recommend this method if you are HIV positive or have an active HSV infection. Internal monitoring also further limits mobility, and you will need to stay in bed once it is in place.

Monitoring Based on Where You Give Birth

If you plan to have your baby at home birth or a birth center, your provider will monitor your baby’s heart rate intermittently using auscultation. This method allows you to move freely and does not require specialized equipment, usually only available in a hospital setting.

If you transfer to a hospital or plan a hospital birth, your monitoring options may differ depending on your specific circumstances. This includes whether monitoring is intermittent or continuous. Some reasons your care provider may prefer continuous monitoring are if you get an epidural, or you have Pitocin, which is synthetic oxytocin to induce or augment your labor, or if you are high risk or run into any complications. A few examples of things that could make a pregnancy high-risk include gestational diabetes or high blood pressure, or if your baby is not developing or growing as well as they should be. 

Understanding Fetal Heart Rate Monitoring and Your Options

Monitoring practices and options can vary widely between hospitals, birth centers, and home settings. Even within the same hospital, policies may differ depending on your provider, your pregnancy risk factors, and how your labor progresses. Before you go into labor, it’s helpful to understand how fetal heart rate monitoring typically works and what options may be available to you.

Monitoring Upon Hospital Admission

If you plan a hospital birth, it is common to be hooked up to a monitor for about 20–30 minutes when you first arrive in labor. This initial monitoring helps your care team assess how your baby is handling contractions and establish a baseline heart rate pattern. If everything looks reassuring, you may be able to have the belts removed and switch to intermittent monitoring.

Research shows that routine monitoring on admission does not necessarily improve outcomes. One Cochrane review found no evidence of benefit from using electronic fetal monitoring upon admission. In fact, the study found that this practice increases the likelihood of a cesarean birth by about 20%. Based on these findings, the authors recommend that an admission CTG should not be used for women who are at low risk when they arrive at the hospital in labor. They also emphasize that patients should be informed that admission monitoring is associated with a higher rate of cesarean birth without clear evidence of benefit.

Effects on Mobility

Continuous electronic fetal monitoring limits your ability to move during labor because the wires connect you to the CTG machine. Research shows that the most effective labor positions are not on your back in a hospital bed. Moving and trying different positions can help labor progress and may even shorten its duration.

Continuous monitoring can also prevent you from laboring in the shower or having a water birth. Some monitors are waterproof; however, not all venues may carry these options. Talk with your doctor or midwife if you plan to use hydrotherapy, to find out whether waterproof monitors are an option.

Mobile Monitoring

Some hospitals offer telemetry monitoring as an alternative to standard electronic monitoring. A telemetry monitor uses a small transmitter, usually placed on your thigh, to send your baby’s heartbeat data to a nurse’s station using radio waves. This setup allows you to move freely and walk around while your provider can continuously monitor your baby’s heart rate. Not every hospital has telemetry monitors available. If you want to utilize this option, ask your care provider whether this option is available where you plan to give birth. Telemetry monitoring provides much more mobility than a traditional CTG machine.

Continuous vs. Intermittent Monitoring

A Cochrane review analyzed 13 trials involving more than 37,000 women who were randomly assigned to either continuous or intermittent fetal monitoring. The review found no difference in the number of babies who died during or shortly after labor. Neonatal seizures were rare and occurred slightly less often with continuous monitoring. There was no difference in the rates of cerebral palsy. However, continuous monitoring was associated with a significantly higher rate of cesarean and instrumental vaginal births. This suggests that while continuous monitoring may slightly reduce the risk of rare neonatal seizures, it also increases the likelihood of interventions during birth.

Monitoring a High-Risk Pregnancy

Care providers almost always recommend electronic fetal monitoring when a baby is at high risk. This makes sense on the surface. However, but there is no hard evidence that continuous electronic fetal monitoring has improved outcomes for babies in high-risk pregnancies. This is echoed in the Cochrane Review mentioned above. 

Why Hospitals Use EFM

After reviewing the research, you might wonder why hospitals continue to use continuous electronic fetal monitoring (EFM) as the standard practice. Several factors contribute to this:

• This is a well-established medical practice. Continuous EFM has been the standard for decades and remains deeply ingrained in the medical model of obstetric care.
• Training and familiarity influence your provider’s practice. Obstetricians, nurses, and medical students receive more training in using continuous EFM and interpreting its tracings than they do in intermittent monitoring or auscultation.
• There is some speculation that hospitals may use continuous monitoring for liability concerns. Continuous monitoring creates a record that can help defend against malpractice claims related to birth complications.
• Continuous monitoring reduces staffing demands. It allows providers to track labor progress remotely rather than being physically present in each room. This setup enables a smaller team to monitor more patients. During the COVID-19 pandemic, many hospitals expanded continuous monitoring to limit staff exposure and support centralized observation from a nurse’s station.

Making Informed Decisions About Monitoring

Some parents may wonder why they would not want to utilize a monitor that ensures their baby is doing well. The key is understanding that every monitoring method has pros and cons. Like many birth interventions, this is not a simple choice between two extremes, either no monitoring at all or continuous internal electronic monitoring. The more you understand your options, the more confident and informed your decision will be.

Although electronic fetal monitoring is often continuous, it does not have to be if both you and your baby are doing well. Ask about your hospital or birth center’s policies for continuous monitoring and the availability of telemetry or waterproof options. You can also discuss this topic ahead of time with your doctor or midwife to get a sense of how they typically handle fetal heart rate monitoring.

You and your care provider share the same goal, which is keeping you and your baby safe while supporting the birth experience you want. Electronic fetal monitoring should always involve informed consent. Use what you have learned to have an informed discussion with your doctor or midwife about your preferences and how different monitoring methods may fit your situation. You have the right to decline or request a specific approach. Your provider can help you navigate this decision, given the particulars of your labor.

Tips for Electronic Fetal Monitoring

If you choose electronic monitoring, a few small adjustments can make the experience more comfortable. The machine has a volume control. If the sound is distracting, lower the volume or turn the monitor so it is not in your view. You might find it helpful to listen to the heartbeat, or you may prefer to tune it out. Encourage your partner to focus on you, not the machine. If it distracts them, turn it down or face it away. If the sound suddenly stops, do not panic. The transducer likely shifted out of place, and your nurse or care provider can easily adjust it. Also, do not worry if the heart rate changes and many variations are completely normal. Leave interpreting the monitor’s readings to hospital staff and keep your attention on the experience of meeting your baby.

Including Preferences for Monitoring in Your Birth Plan

This is an intervention you may want to include in your birth plan. The real value of a birth plan lies in the preparation and discussing your preferences with your doctor or midwife ahead of time so you are in alignment.

The Pregnancy Podcast has many resources to help you craft a birth plan:

• Guide to Creating Your Birth Plan
• Get a copy of Vanessa’s birth plan
• Your Birth Plan book
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