What is a Fetal Monitor?

What is a Fetal Monitor?

A fetal monitor is a device created to track and record fetal heart rate (FHR) and the mother’s uterine contractions. Monitoring these parameters provides obstetrics clinicians the information required to detect fetal distress and determine if an intervention is necessary.

These monitors are highly recommended for high risk pregnancies (usually tied to diabetes or preeclampsia). They’re helpful in identifying patterns when administering any labor medication.

What are the different types of fetal monitoring?

There are two types of fetal monitoring. External monitoring occurs on the outside of the abdomen. Internal monitoring occurs on the inside of the uterus.

External Monitoring: Usually, a transducer is attached to the belly, this can happen during checkups or during labor. There are different ways to monitor from the outside:

• Fetoscope: similar to a regular stethoscope, the cone shape device is pressed against the mother’s belly to listen to the heartbeat of the fetus.
• Tocodynamometer: a pressure sensitive device attached to the abdomen to record contractions.
• Handheld Doppler Ultrasound: this one is usually used during prenatal visits to listen to the heartbeat beat and depending on the device, different kinds of readouts can be seen on its screen (if it has one).
• Continuous Doppler Ultrasound: a device strapped to the abdomen to continuously monitor the baby’s heart rate during labor.

Internal Monitoring: used less often and only when the amniotic sac has broken and the cervix is open. Your provider may want to do this when external monitoring results are unreliable or when he or she needs a more precise monitoring.

• Fetal scalp electrode: a thin wire that needs to be tied around the baby’s head. This wire provides the heart rate.
• Intrauterine pressure catheter: a thin tube placed through the cervix to relay the uterine pressure readings.

Both methods provide the same readings of FHR and the mother’s uterine contractions. The external method is less invasive and is more common. The internal method is used less, it can cause discomfort, but it provides more precise readings due to where its placed.

How does a fetal monitor work?

As discussed in the previous section, these external or internal tools are used to monitor FHR and contractions. But how do these tools work, and how do these parameters affect both patients?

• Fetal Heart Rate: Using a fetoscope, ultrasound, or fetal scalp electrode, the professionals listen to the heart rate of the baby. They look for intensity, rhythm, and bpm. This can help identify any possible issues regarding the pregnancy.
• Contractions: The external method uses a tocodynamometer to monitor the changes in pressure to record any contractions. The internal one uses a pressure transducer that identifies changes in pressure, which leads to more accurate readings.

Why is it essential to monitor the FHR?

The normal or average fetal heart rate ranges from 110 – 160 bpm. By monitoring the FHR, doctors can detect if it’s too high, too low, or if it changes too much over a period of time. Additionally, it can discover irregularities that could mean that they need to take action to ensure the fetus’s health.

What are the risks and limitations of fetal monitoring?

While fetal monitors are a great tool to assist medical professionals, they’re not 100% accurate, and in the case of the internal monitors, they’re not 100% safe.

• Using an external monitor during labor can help to keep track of the whole picture, but it also limits the mother’s movement. Sometimes being stationary can result in a longer labor process, because movement can help with pain management, making the labor process run in a more natural way.
• Constant monitoring can lead to false positives, showing slightly abnormal patterns while the baby is still doing fine. This can lead to unnecessary C-sections or other invasive procedures.
• Internal monitoring can cause infections, injuries to the baby’s scalp, and even the transmission of diseases. The risk for this is low, but still falls under the realm of probabilities.

Why does the FDA discourage at-home fetal monitors?

The FDA discourages them because even when external fetal monitors are safe and are not prone to cause harm. They’re only that safe under the handle and supervision of trained professionals. While using it at home, people can encounter the following:

• Lacks control over how often they should be used.
• Require training to use it and interpret the reading, leading to unnecessary stress and false positives.
• In some instances, they can overheat the tissue and harm it.

What is recommended instead is to track the baby’s movements during your pregnancy and talk to your provider about what you are feeling versus what you are supposed to feel at that stage.

What are some examples of fetal monitors?

Examples of Fetal Monitors

In the United States, the two primary manufacturers of fetal monitors are GE and Philips, with GE fetal monitors being significantly more popular.

GE Corometrics 250 Series

The GE Corometrics 250 Series includes two popular hospital models: the 256cx, a fetal monitor, and the 259cx, which measures both fetal and maternal vital signs. The 259cx is more frequently requested because it measures fetal heart rate (including waveform), contractions, maternal SpO2, ECG, NIBP, and temperature. It can monitor twin pregnancies simultaneously and also allows for internal measurement of fetal heart rate and contractions.

GE Corometrics 170 Series

The GE 170 series Corometrics fetal monitors are more streamlined than the 250 series so that they can be used in facilities ranging from physicians’ offices to clinics to hospitals.  However, it is important to note that these monitors cannot provide internal monitoring, so they are best utilized for check-ups and routine pregnancies.  The two models in the series are the 171 and 172, the only difference being that the 172 can monitor twins while the 171 is for single pregnancies.  The 170 series measures both fetal heart rate and Toco, though they cannot digitally display graphs; instead, if the clinician desires a graph of the fetal heart rate, they will need to print it out and study it on the paper printout.  These models also differ from the 250 series because they cannot measure maternal vitals and focus exclusively on the fetus.

GE Novii Wireless Patch System

The GE Novii wireless patch system is a new fetal monitoring solution for low-risk pregnancies. It consists of the Novii Patch, Novii Pod, and Novii Interface. The single-use Novii Patch adheres to the abdomen and captures electrical signals, which are then sent to the reusable Novii Pod via magnetic connection. The Pod processes the data and transmits it via Bluetooth to the Novii Interface, which connects to a 259cx Corometrics fetal monitor and has charging bays for the Pod. This wireless capability allows patients to remain mobile and even bathe during labor. Unlike traditional monitors, the Novii system differentiates between maternal and fetal ECGs without Doppler ultrasound and detects contractions by measuring uterine EMG signals.

How can Soma help?

Soma Tech maintains a constant stock of all types of fetal monitors from multiple manufacturers.  In addition to fetal monitors, we are also experts on incubators, infant warmers, and other equipment for NICU or labor and delivery departments.  As a vendor-neutral supplier, we can help our customers consider their options among many models and manufacturers, so contact your dedicated sales rep to learn which model would work best for your facility!