Fetal heart monitoring is a common practice used by healthcare providers to examine a baby’s heart rate during the latter stages of pregnancy and throughout labor and delivery.
Your healthcare provider uses fetal heart monitoring to gain valuable insights into your unborn child’s health by observing how their heart rate changes based on various intrauterine conditions. Any irregularities in these patterns may signal potential issues, such as a lack of oxygen or other complications.
Editor’s Warning About Mobile Apps: Before we jump into the types of fetal heart monitoring and fetal heart tracing and why they are needed, we highly suggest you have a trained medical professional conduct proper monitoring. While products are available on the open market, including mobile apps, medical professionals carefully analyze patterns to detect signs of conditions such as hypoxia, where fetal tissues do not receive sufficient oxygen. A study published in 2019 found that 33% of mobile apps provided incorrect heart monitor readings, and many mobile apps provided incorrect medical information or failed to disclose critical medical warnings.
Types of Fetal Heart Monitoring: How They’re Performed And What They Reveal
Fetal heart rate (FHR) monitoring is an essential tool used by healthcare professionals to evaluate the condition of a fetus during pregnancy. Baseline rate, variability, accelerations, and decelerations are the primary components assessed to interpret FHR.
Baseline FHR
Baseline FHR is determined over a 10-minute segment. Your provider averages the segments that are most stable and horizontal. For Baseline FHR the normal baseline ranges from 110 to 160 beats per minute (bpm). If your baby’s baseline exceeds 160 bpm, it is called tachycardia, while a baseline below 110 bpm is called bradycardia.
Variability
Variability in FHR signifies fluctuations around the baseline. Normal variability, essential for a healthy tracing, measures between 5 and 25 bpm. Elevated variability measures above 25 bpm for more than half an hour, whereas low variability, often indicating potential issues like fetal hypoxia, measures less than 5 bpm for over 50 minutes.
Accelerations
Accelerations are brief increases in heart rate, exceeding 15 bpm in amplitude, reaching a peak in under 30 seconds. These usually last between 15 seconds and 10 minutes and often coincide with fetal movements, indicating an active and well-oxygenated fetus.
Your doctor may attempt to create acceleration in several ways.
- Rocking the mother’s abdomen.
- Gently press on the baby’s head through the cervix using their finger.
- Acoustic stimulation using short bursts of sound.
- Having the mom-to-be drink fluids or eat a small amount of food.
Decelerations
Decelerations involve a drop in FHR by more than 15 bpm and can be categorized as early, variable, or prolonged.
- Early decelerations are short, shallow declines in heart rate that typically align with uterine contractions, often attributed to head compression rather than distress.
- Variable decelerations exhibit a rapid decrement in heart rate, reaching their lowest point quickly, and vary significantly in shape and size. They often occur with contractions but recover swiftly to the baseline level.
- Prolonged decelerations last longer than three minutes. If such decelerations extend beyond five minutes with concurrently reduced variability and bradycardia, it may suggest acute fetal distress.
Carefully assessing all these components in fetal heart monitoring allows healthcare providers to make informed decisions about maternal and fetal health, ensuring timely identification of potential complications during pregnancy and childbirth.
Fetal Heart Tracing’s Role In Fetal Heart Monitoring
I wanted to clarify a misconception I’ve heard often from parents. There is a difference between Fetal Heart Monitoring and Fetal Heart Tracing.
Specifically, fetal heart tracing refers to collecting fetal heart monitoring data to analyze patterns. Using an electronic fetal monitor, the results are outputted to a piece of paper or digital graph that illustrates fetal heart rate patterns and contractions, allowing healthcare providers to assess the baby’s status in detail.
Key Differences between Fetal Heart Tracing and Tracking:
| Aspect | Fetal Heart Tracing | Fetal Heart Rate Tracking |
|---|---|---|
| Tool Used | Electronic fetal monitor | Doppler, fetoscope, or EFM |
| Recording | Continuous graphical record | Not necessarily graphical or continuous |
| Purpose | Evaluate patterns and correlations | Check or monitor heart rate |
While fetal heart tracing is one way to track fetal heart rate, not all heart rate tracking involves tracing. Tracing provides more detailed information about patterns and potential issues. It is typically utilized for high-risk pregnancies or in cases when your healthcare provider wants or needs a little bit more information to ensure a healthy delivery.
Fetal heart tracing is a complex process, so much so that the University of Michigan offers a free “second look” iOS app that allows healthcare professionals to regularly re-assess their knowledge of reading and interpreting data from FHT graphs.
Why Is Fetal Heart Monitoring Needed During Pregnancy And Labor?
In the latter stages of pregnancy, an increased heart rate is typical as the fetus becomes more active. Nonetheless, complications such as hypoxia can result in a slower heart rate. Regular nonstress tests, conducted weekly or more frequently depending on circumstances, can be beneficial in monitoring the well-being of both the expectant parent and the fetus.
During labor, fetal heart monitoring is essential to identify deviations from typical patterns. Recognizing these changes enables healthcare providers to address potential medical issues promptly. This monitoring also differentiates between necessary and unnecessary interventions, ensuring only required treatments are administered.
A reassuring FHR pattern can comfort both the expectant parent and the medical team, highlighting the safety of continuing with labor and delivery.
Conducting Fetal Heart Rate Monitoring
Two types of fetal heart rate monitoring options exist: internal and external.
External Fetal Heart Rate Monitoring
External fetal heart rate monitoring involves specialized equipment that utilizes a fetoscope or Doppler device to track the fetal heart rate (FHR). This device is attached to the mother’s abdomen and captures the baby’s heart sounds, relaying them to a computer for analysis. The recorded FHR can then produce a fetal heart tracing document when required, and healthcare professionals can interpret that document.
Typically performed in a medical facility, such as a hospital or doctor’s office, this process requires the patient to be in a lying or reclined position. The session usually takes about 20 minutes. During this time, obstetricians regularly assess the fetal heart tracing at set intervals. More frequent reviews may occur if there are any concerns.
There are three main types of external fetal heart monitors:
Fetoscope: This is the least sophisticated option. A fetoscope is an instrument similar to a stethoscope that a doctor would use to listen to your heart and lungs, but it is specifically designed for detecting your baby’s heartbeat. The device has a cone-shaped end that is pressed against your abdomen, allowing your healthcare provider to hear the baby’s heartbeat directly.
Handheld Doppler Ultrasound: A handheld Doppler ultrasound device uses sound waves to measure the fetal heart rate. Healthcare providers commonly use these devices during prenatal appointments. To use it, the provider applies a small amount of gel to your abdomen and places the device’s probe into the gel. The Doppler picks up the baby’s heartbeat, which is then displayed on a screen. While handheld Doppler devices are available for at-home use, the Food and Drug Administration (FDA) advises against their use outside a clinical setting.
Continuous Doppler Ultrasound: During labor and delivery, your provider may use continuous electronic fetal monitoring through a Doppler ultrasound. This involves securing the ultrasound probe to your abdomen with an elastic strap. A second strap holds a sensor that monitors your contractions. Both devices are connected to a monitor, which continuously displays your baby’s heart rate and provides detailed information about your labor progress.
Sometimes, a less sophisticated version of the Doppler Ultrasound will allow a medical professional to examine a baby’s heart rate on the device’s display. My wife gave birth to our four children at home, and her midwife, a nurse practitioner, used a portable fetal Doppler to listen to our baby’s heart rate when at-home check-ups were involved.
Here’s what a portable fetal Doppler device looks like:
It should be noted that my wife was considered very low risk during all four pregnancies, making the process a bit easier in terms of overall fetal heart rate monitoring. Still, because she was in her mid-30s during the birth of our fourth child, Doppler ultrasounds and general ultrasounds (a first for her pregnancies) were performed in our midwife’s OB/GYN office.
Internal Fetal Heart Rate Monitoring
Internal fetal heart rate monitoring is less common and requires an electronic transducer to be connected directly to the fetal skin. A wire electrode is attached by your doctor to the fetal scalp or another body part by way of the cervical opening. Doctors will often refer to this electrode as a spiral or scalp electrode.
According to the Universe of Rochester Medical Center, “Internal monitoring provides a more accurate and consistent transmission of the fetal heart rate than external monitoring because factors such as movement do not affect it. Internal monitoring may be used when external monitoring of the fetal heart rate is inadequate, or closer surveillance is needed.”
Always consult your medical provider regarding how and when fetal heart tracing will be conducted and why the process is needed.
How Fetal Heart Monitoring And Fetal Heart Tracing Are Conducted During Labor and Delivery.
The process for fetal heart rate monitoring during labor involves two belts that are placed around the mother’s abdomen:
- One belt employs Doppler ultrasound technology to track the baby’s heart rate.
- The other measures the timing and strength of uterine contractions.
The information from the belts is then outputted as part of the fetal heart tracing process so your healthcare provider can analyze it as needed.
Why Monitoring And Tracing Are Important During Labor And Delivery
Fetal Heart Monitoring during labor helps doctors monitor a baby’s oxygen levels and tells them if immediate medical intervention may be required. Fetal heart tracing (FHT) assesses the fetal heart rate (FHR) and its response to uterine contractions. This helps detect potential issues, such as fetal distress, that could indicate insufficient oxygen supply or other complications.
FHR can also alert your medical provider if Fetal Hypoxia (low oxygen levels) may require immediate medical intervention, such as changing the mother’s position, providing oxygen, or delivering the baby.
In some cases, if a baby isn’t tolerating contractions well or other signs of distress worry your healthcare provider, they may want to expedite delivery through assisted vaginal delivery or a cesarean section (c-section).
Johns Hopkins University notes that fetal heart rate monitoring is beneficial during pregnancy because doctors can determine if the following circumstances affect fetal heart rate:
- Uterine contractions
- Pain medicines or anesthesia given to you during labor
- Tests done during labor
- Pushing during the second stage of labor
This comprehensive approach ensures the well-being of both mother and baby by providing critical real-time data that aids in making informed medical decisions.
Fetal heart monitoring is a general practice used by doctors, nurses, midwives, and other health professionals to gain a baseline understanding of any underlying issues your baby may face at any given moment. In most cases, it is a non-intrusive process, and in my experience, it’s a quick tool for giving parents a little peace of mind about their developing unborn child.
If your doctor chooses to perform fetal heart tracing during your pregnancy, labor, or delivery, remember that it’s not an immediate cause for concern; they may just be performing additional due diligence because they want to cover all of their bases. Never be afraid to ask your doctor questions that put your mind at ease; they are there to do right for you and your baby.
