Since it was first developed more than 50 years ago, electronic fetal monitoring (EFM) has become standard practice in labor and delivery and an expectation for many expectant moms delivering in U.S. hospitals. However, research from the Cochrane Database of Systematic Reviews has shown that this level of continuous monitoring may not be necessary or the optimal tool for all pregnant and laboring patients.¹ For pregnancies where mom and baby are low risk, less machine monitoring and more basic tools for assessment may be indicated. Palpating the uterus, intermittent auscultation of the fetus' heart rate, observation and evaluation are valuable tools. It can be time-consuming to teach these skills but well worth the effort to improve maternal and fetal outcomes, even when using available electronic tools.

Electronic Fetal Monitoring: The Basics

The goal of any fetal monitoring is to decrease morbidity and mortality in both moms and babies. Prior to the advent of EFM, intermittent auscultation (IA) and fetal scalp blood sampling for pH monitoring were the usual methods for assessing fetal well-being. IA is still an option, but less common in U.S. hospitals., according to a study from the American College of Nurse-Midwives.² In addition, this method detects changes in fetal heart rate (FHR) during monitoring, usually during contractions, but does not pick up overall FHR variability—an important indicator of distress in high-risk pregnancies.

Electronic fetal monitoring may be accomplished by external or internal methods. Traditional electronic fetal monitoring involves the placement of two transducers (an ultrasound to acquire FHR and a TOCO to pick up contractions) on the mom's abdomen. This placement can hamper maternal movement, and as the baby moves, the heart rate can be lost. This method also only measures the presence and frequency of contractions, not their strength. According to research published in American Family Physician (AFP), external monitoring may be difficult due to above-average maternal BMI and fetal location or presentation.³

Internal monitoring is accomplished by the placement of an intrauterine pressure catheter (IUPC) to measure uterine activity (UA), both frequency and strength, and/or a fetal scalp electrode (FSE) to monitor FHR. Internal monitoring is less common given that this requires membranes to be ruptured and that there is sufficient cervical dilatation. It also carries an increased risk of infection due to the invasive nature of the procedure.

Standards for Fetal Monitoring

A landmark fetal monitoring classification system was developed by the National Institute of Child Health and Human Development in 2008, and it's still in use today.⁴

It uses a three-tiered system to describe:

Uterine contractions
Baseline FHR
Variability of FHR
Presence of accelerations or decelerations and trend patterns over time

The tiers are normal, indeterminate, and abnormal, or otherwise indicated as Category I, II, or III.

On top of this tier system, standards for EFM are set by three different organizations: the International Federation of Gynecology and Obstetrics (FIGO), the American College of Obstetrics and Gynecology (ACOG) and the National Institute for Health and Care Excellence (NICE).^5,6,7 No matter which guidelines are used, there is only modest interobserver agreement in tracing interpretation, reports a study published in Acta Obstetricia et Gynecologica Scandinavica.⁸

The study found good agreement in all guidelines when the tracing was Category I. Using ACOG guidelines, there was a tendency to classify abnormal patterns in Category II ("watch and wait") vs. Category III ("immediate intervention"). The FIGO and NICE guidelines led to greater interobserver agreement and accuracy, even with wide gaps in years of provider experience. Regardless of which guidelines are used, adequate training is of paramount importance.

Should Continuous Electronic Fetal Monitoring Be the Standard?

Although continuous fetal monitoring reduced the incidence of neonatal seizures, it does not reduce infant mortality "or other standard measures of neonatal wellbeing," according to a review published in Cochrane.⁹ The review authors recommend that clinicians discuss a patient's individual preferences and medical needs during labor before deciding on intermittent monitoring, continuous monitoring, or another option.

However, most recommendations agree that continuous EFM is appropriate for monitoring high-risk pregnancies, such as placental insufficiency, preeclampsia, hypertension, or fetal growth restriction. If intermittent auscultation reveals Category II ("indeterminant") findings, continuous EFM should be instituted until it is determined the fetus is stable.

For low-risk pregnancies, intermittent auscultation can be used along with palpation to assess contraction strength. Standards published in the American College of Nurse-Midwives Clinical Bulletin call for performing intermittent auscultation as often as every 15 minutes during the active phase of the first stage of labor, and every five to 15 minutes during the second stage of labor.²

This obviously requires a 1:1 nursing assignment to care for the laboring person, which can be a barrier for many hospitals. Central EFM allows one nurse to monitor many laboring patients and alert another provider when concerning patterns are identified, but it seldom improves patient satisfaction.

Monitoring Options

One of the most frequent complaints about continuous EFM is the discomfort of the abdominal transducers and belts for long periods of time, perhaps even several days. Additionally, with traditional cabled monitors, moms are unable to walk, take a shower, use a birthing pool, or do other activities that may not only bring comfort but promote the progression of labor.

Some additional monitoring options that are currently available aim to address these issues.

Telemetry

Devices, such as the Mini Telemetry System, allow for maternal ambulation or even water laboring if desired, thanks to waterproof transducers. This simple solution utilizes the traditional transducers used with Corometrics Fetal Monitors, but in a mobile version, allowing the freedom of movement that many moms desire all while still continuously monitoring FHR and uterine activity (UA). Additionally, features include the ability to monitor maternal heart rate (MHR) via ECG as well as the option for internal monitoring utilizing an IUPC and or an FSE. This device simply plugs into most current GE Corometrics Fetal Monitors utilizing interchangeable transducers for ease of use. When the transmitter is fully charged, it provides moms up to 12 hours of battery life and the freedom to move up to 500 meters from the Fetal Monitor while still providing key information clinicians need to make safe and informed decisions during ambulation.

Novii Wireless Patch System

The Novii Wireless Patch System enables freedom of movement with a cableless, belt-free laboring experience that can help empower moms and enable caregivers to provide the labor experience their patients have always hoped for. This wireless monitoring system comprises a five-electrode patch and a small pod that transmits the FHR, MHR, and UA via Bluetooth. The Novii Patch and Pod, when connected, are waterproof and can be left in place during a bath or shower. In addition to being an excellent tool in providing patients with mobility, comfort, and water labor, it also can provide a solution for those truly difficult to monitor patients. Because Novii utilizes electrical activity (fetal ECG, maternal ECG, and uterine EMG) to acquire signals instead of ultrasound and TOCO transducers, it is often a superior tool for monitoring patients with a high BMI.

Like other adhesive patch sensors, a small percentage of users have reported skin irritation from this new technology, and this new method of capturing FHR may not work in all situations.

Back to the Basics

Each of the many options for monitoring moms and babies during labor and delivery has value at the right time and place. In addition to advanced technologies, clinicians always have the most basic, but often crucial, tools at their disposal—their hands, eyes, and ears. Using hands to palpate contractions, feeling for fetal positioning to help guide maternal position changes in labor, listening to mom's verbal cues for assessment of pain, listening for indistinct ques indicating labor progression, feeling the warmth of a mom who is developing a fever; these are all some of the finest tools care providers can employ to ensure safe and effective care while delivering the experience moms deserve.

Care during labor and delivery should not be a one-size-fits-all approach. A healthy delivery for mom and baby can be accomplished with a critical approach to the proper tools available. This mindset and utilization of all the tools available can empower both caregivers and patients to drive toward the best possible outcomes.

References:

Devane D, Lalor JG, Daly S, et al. Cardiotocography versus intermittent auscultation of fetal heart on admission to labour ward for assessment of fetal wellbeing. Cochrane Database of Systematic Reviews. doi.org/10.1002/14651858.CD005122.pub5
American College of Nurse-Midwives. Intermittent auscultation for intrapartum fetal heart rate surveillance. Journal of Midwifery & Women's Health. 2015;60(5):626-632. doi:10.1111/jmwh.12372
Arnold JJ, Gawrys BL. Intrapartum fetal monitoring. American Family Physician. 2020;102(3):158-167. https://www.aafp.org/pubs/afp/issues/2020/0801/p158.html
Robinson B, Nelson L. A review of the proceedings from the 2008 NICHD workshop on standardized nomenclature for cardiotocography. Reviews in Obstetrics and Gynecology. 2008;1(4):186-192. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2621055/
Ayres-de-Campos D, Spong CY, Chandraharan E. FIGO consensus guidelines on intrapartum fetal monitoring: Cardiotocography. International Journal of Gynecology & Obstetrics. 2015;131(1):13-24. doi:10.1016/j.ijgo.2015.06.020
American College of Obstetricians and Gynecologists. FAQs: Fetal heart rate monitoring during labor. https://www.acog.org/womens-health/faqs/fetal-heart-rate-monitoring-during-labor. Accessed November 11, 2022.
National Institute for Health and Care Excellence. Intrapartum care for healthy women and babies. NICE Guidance. https://www.nice.org.uk/Guidance/CG190. Accessed November 11, 2022.
Santo S, Ayres-de-Campos D, Costa-Santos C, Schnettler W, et al. Agreement and accuracy using the FIGO, ACOG and NICE cardiotocography interpretation guidelines. Acta Obstetricia et Gynecologica Scandinavica. 2017;96(2):166-175. doi:10.1111/aogs.13064
Alfirevic Z, Devane D, Gyte GM, et al. Continuous cardiotocography (CTG) as a form of electronic fetal monitoring (EFM) for fetal assessment during labour. Cochrane Database of Systematic Reviews. 2017;2(2). doi:10.1002/14651858.cd006066.pub3

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