Ask any woman about their labor and delivery and fetal heart tracing (FHT) is sure to come up. Assessing fetal heart tones has been practiced in some capacity or another since the 1800’s. Accomplished through stethoscopes in the 1800’s and Pinard fetoscopes into the 1950’s until in 1958, when a doctor from Yale University was able to continuously monitor fetal heart tones and identify fetal distress. With the advancement of ultrasound technology use in pregnancy, fetal heart monitoring (FHM) entered maternity wards in the 1970’s. This move had very little evidence to support it and was mainly fueled by the monitoring industry. Since then, methods of fetal heart monitoring have expanded significantly.
FHT can gives us many valuable insights into fetal status, how labor is progressing, and can help to clue us in to problems that may be arising. Because labor is such a crucial time for the health of both mom and baby it is no surprise that the preference has leaned heavily towards continuous fetal monitoring.
“Belly bands” are the combination of technologies that create a visual read out of fetal heart tones in relation to contractions. These external monitors trace fetal heart rate and maternal uterine contractions in relation to one another. Continuous FHM can also be accomplished internally by the use of a fetal scalp electrode (FSE) which monitors fetal heart rate and an intrauterine pressure catheter (IUPC) which monitors contractions. These methods of continuous FHM have their benefits and drawbacks. External monitors tend to be very positional and in many cases need frequent readjusting. They also don’t work well in mother’s with elevated BMI or in certain pathologies like polyhydramnios. Internal monitors, although highly accurate elevate the risk of maternal and fetal infection. Both methods produce a visual read out and both restrict maternal movement. There is a preponderance of evidence to suggest walking and positioning can aid in labor progression. Subsequently, these methods can be quite cumbersome in mother’s wishing to deliver naturally.
Although continuous FHM is the mainstay intervention for most women, intermittent auscultation (IA) continues to be used. For several decades IA has been the recommendation for health mothers with low risk pregnancies. This was mainly because continuous fetal monitoring meant being hooked up to a monitor. As you can imagine, this is less than ideal for labor positions as it restricts maternal movement. However, the accuracy of IA has been heavily debated as it tends to be more subjective and requires clinical expertise (Blix, et al., 2019). As any labor nurse will tell you, labor can become an emergency in a second; therefore IA has the potential to increase the risk that a problem may be caught later rather than sooner.
In recent years, a new monitor has been developed that combines the benefits of continuous (FHM) with the freedom of movement that intermittent auscultation provides. The Novii patch is not limited by body habitus or by pathology. It produces a fetal heart tracing using the same technology as an electrocardiogram, then transmits the information via Bluetooth to the monitor which creates a visual tracing. What’s more the Novii patch is waterproof allowing for the use of hydrotherapy in labor. Utilizing this technology it is no longer necessary to sacrifice accuracy for maternal intervention or visa-versa. This is hugely empowering for mothers who no longer feel tied down either physically or in terms of options. It has the potential to improve outcomes by meeting the goals of medical professionals and laboring mothers alike. In the past, these were often at odds with one another and labor nurses were torn between supporting maternal wishes and the need for monitoring fetal status.
We’ve come a long way from the Pinards of the past to the Noviis of today. Technology continues to free mothers from the confines of the labor bed. Selecting the best method of FHM requires individual assessment of maternal wishes, pathologies, and desired pain interventions. Understanding the risks, benefits, and alternatives to each can empower mothers in their labors and facilitate improved perinatal outcomes.
Blix, E., Maude, R., Hals, E., Kisa, S., Karlsen, E., Nohr, E. A., … Kaasen, A. (2019). Intermittent auscultation fetal monitoring during labour: A systematic scoping review t External monitors - Ultrasound transducer & Tocometer o identify methods, effects, and accuracy. Plos One, 14(7), e0219573. https://doi-org.libpublic3.library.isu.edu/10.1371/journal.pone.0219573
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