Evidence-Based Fetal Monitoring

© 2012 By Rebecca Dekker, PhD, RN, APRN

I’ve written before about the lack of evidence for continuous electronic fetal monitoring, but recently I felt the need to write further on this issue. I feel strongly that our maternity care in the U.S. has headed down the wrong path with fetal monitoring. Yes, I believe that it is beneficial to monitor a baby’s heart rate during labor. But the majority of American women receive the wrong type of fetal monitoring for their situation. They receive something called continuous electronic monitoring instead of intermittent auscultation. 

The vast majority of American women are attached to continuous fetal monitors during labor
Image source: Robenjoyce

But what’s the big deal? Well, first of all, everybody else in the world tends to follow our example. U.S. hospitals have invested over $700 million dollars in electronic fetal monitoring equipment that is NOT evidence-based and contributes to unnecessary Cesarean deliveries. Do you think developing countries around the world should be following our example, spending precious resources on this equipment? Second, most women in our country do not give informed consent for electronic fetal monitoring. The vast majority of women in the U.S. have no idea about the benefits and risks of the #1 most common obstetric procedure used in labor and delivery– electronic fetal monitoring.

One of my readers recently told me that she was going to request intermittent auscultation (the evidence-based option for fetal monitoring) from her care provider—and her doctor agreed! We were both curious to see how the hospital would react to her seemingly benign request for evidence-based monitoring.

I’ve decided to break this topic into two articles. In this article, I will discuss the evidence for fetal monitoring. In my next article, I will share with you one mother’s quest for evidence-based fetal monitoring, and talk about how other pregnant women can follow her example. You can read the next article that shares my reader’s story here.

What are the different types of fetal monitoring?

Electronic fetal monitoring (EFM) is when you use a Doppler ultrasound machine to monitor the baby’s heart rate while simultaneously using a pressure sensor to monitor the mother’s contractions. Both of these sensors are linked to a recording machine, which shows a print-out or computer screen of the baby’s heart rate and the mother’s contractions. (Alfirevic, Devane et al. 2006). There are 2 types of EFM: continous and intermittent.

• According to the 2007 “Listening to Mother Survey,” 87% of U.S. described experiencing continuous electronic fetal monitoring during labor (Declercq, Sakala et al. 2007). However, just because the monitoring is continuous does not mean that a clinician is continuously watching the monitor. Most of the time, a clinician determines and evaluates the fetal heart rate every 30 minutes during the active stage of first stage labor (when the mother is dilated 5-10 cm) and every 15 minutes during the active pushing phase of labor.  However, if the mother is high risk, or if she is being given Pitocin, then this may be done more frequently (ACOG, 2009).

• In 4% of U.S. women, EFM is used only intermittently during labor (Declercq, Sakala et al. 2007). This is called intermittent electronic fetal monitoring, and it generally means that you have to wear the machine sensors for 20-30 minutes of every hour (I could not find any guidelines that recommend a specific frequency and length of intermittent EFM).

Intermittent auscultation is used with 3% of U.S. women during labor (Declercq, Sakala et al. 2007). With intermittent auscultation, the care provider listens to the baby’s heart rate for about 60 seconds using a fetal stethoscope (fetoscope or Pinard) or a hand-held Doppler ultrasound device. While listening, the care provider also palpates the mother’s contractions by placing a hand on the abdomen. Most guidelines agree that intermittent auscultation should be done every 15-30 minutes during the active phase of the first stage of labor (from 5-10 cm dilation) and every 5-15 minutes during the pushing phase of the second stage of labor (AWHONN, 2008).

What is the purpose of using these tests?

Theoretically, the purpose of monitoring the baby’s heart rate during labor is to identify oxygen problems in the baby so that you can intervene and prevent complications such as cerebral palsy, brain damage, newborn seizures, or death. However, at the same time, you do not want these tests to increase the risk of unnecessary interventions, such as unnecessary Cesarean delivery or forceps/vacuum delivery (ACOG, 2009).

So which method is better for a woman in labor?

Based on the evidence, the best option for most women and babies is intermittent auscultation.

In a Cochrane review (Alfirevic, Devane et al. 2006), researchers compiled the results of 12 randomized, controlled trials with more than 37,000 women. Unfortunately, many of the studies were of poor quality—however, 2 of the studies were of excellent quality. In all of these studies, women were randomly assigned to either receive continuous EFM or intermittent auscultation. These classic research studies took place mostly in the 1970′s and 1980′s– meaning that this evidence has been around for at least 30 years.

There were no differences between women who received intermittent auscultation and those who received continuous EFM in perinatal mortality, cerebral palsy, Apgar scores, cord blood gasses, admission to the neonatal intensive care unit, or low-oxygen brain damage. These findings were consistent in both low-risk and high-risk women. There was a lower risk of newborn seizures in the continuous electronic fetal monitoring group; however, overall, seizure events were very rare (0.2%)

Women in the continuous EFM group were 1.7 times more likely to have a Cesarean and were slightly more likely to have a forceps/vacuum delivery when compared to women in the intermittent auscultation group. Women in the continuous EFM group were also more likely to require pain medication.

Interestingly, the researchers found an interaction between Cesarean rates and continuous EFM. This means that in hospitals where there are higher Cesarean rates, continuous EFM may lead to an even higher risk of Cesarean delivery.

As stated earlier, one of the purposes of continuous EFM is to prevent cerebral palsy. However, researchers have found that continuous electronic fetal monitoring is a very poor test for this purpose. False positive rates for predicting cerebral palsy are as high as 99.8% (that’s basically 100%), even in the presence of “ominous signs,” such as multiple late decelerations or decreased variability (Nelson, Dambrosia et al. 1996).

The evidence against continuous electronic fetal monitoring is so clear that the U.S. Preventive Services Task Force issued a recommendation saying that continuous electronic fetal monitoring should NOT be used in low risk women. Even ACOG has endorsed intermittent auscultation as an “appropriate and safe alternative” to electronic fetal monitoring (ACOG, 2009).

It is estimated that EFM leads to one additional Cesarean for every 58 women monitored and one additional Cesarean for every 12 high-risk women in labor (Alfirevic, 2006). Some guidelines suggest that EFM should be used when there is an abnormal intermittent strip, or with severe pregnancy-related illness, multiples, post-term pregnancy, VBACs, intrauterine growth restriction, premature rupture of membranes, epidurals, and Pitocin (Bailey, 2009; ACOG, 2009). However, this recommendation is based on clinical opinion, as there is no research evidence to support this recommendation.

My doctor says that they will just “put me on the monitor” for 20 minutes of every hour. Is that any better than continuous electronic monitoring?

There is no evidence that intermittent monitoring with the electronic fetal monitor is any better than continuous electronic monitoring. In one study (Herbst & Ingamarsson, 1994),  researchers randomized more than 4,000 high-risk women to receive either continuous EFM or intermittent EFM. They defined intermittent EFM as being on the monitor for 10-30 minutes every 2 hours, with stethoscope auscultation every 15-30 minutes in between monitoring periods. The researchers found no differences in any outcomes.

There are no studies that compare intermittent EFM with intermittent auscultation. However, because intermittent auscultation is superior to continuous EFM—and continuous EFM and intermittent EFM have similar outcomes—it is possible that intermittent auscultation is also better than intermittent EFM.

I don’t think I mind wearing the electronic monitor. What harm could it really do?

To make a fully informed choice, you need to understand the risks and benefits of the electronic fetal monitor. Compared to intermittent auscultation, continuous EFM has the benefit of a decrease in the risk of newborn seizures (a rare outcome). However, it also increases the risk of Cesarean delivery, increases the risk of forceps/vacuum assistance, and increases the risk that you will need pain medication.

In addition to these risks, EFM restricts your ability to walk and change positions. Even a portable or “wireless” monitor is cumbersome, restricts the ability to use water immersion to ease pain, and likely carries with it the same risks as regular EFM. Watching the monitor can create fear and distraction. Many caregivers watch the monitor instead of actually watching and caring for the laboring woman! A fundamental principle that we teach nursing students in nursing school is “Look at your patient, not the monitor.” Having a monitor in the room makes it easier for people to focus on the monitor, not the mother and baby. It also makes it easier for the nurse to monitor the woman from outside the room—possibly decreasing the amount of support a woman could get from her nurse.

If intermittent auscultation has the best outcomes, why don’t more hospitals use it?

Liability. Various hospital administrators need the electronic recording archived in their computer database in case of a lawsuit. With intermittent auscultation, the care provider can document what they hear, but there is no “strip”—there is no continuous electronic recording.

Lack of resources. Many hospital labor and delivery units may own only 1 or 2 handheld Dopplers—or none at all—and if they do own one, it may have “walked off” and can’t be found anywhere on the unit.

Time. The nurse, midwife, or doctor has to actually be at the bedside of the woman every 15-30 minutes and take a minute or two to listen to the heart rate while palpating the contraction. It is easier for nurses to just look at the monitor on a screen at the nurse’s station.

Big Business. Electronic fetal monitoring is a big business. There are approximately 28,000 fetal monitors in more than 3,400 hospitals in the US, representing an investment of over $700 million dollars. I find it interesting that hospitals can spend more than $200,000 per hospital on electronic monitor systems, but they cannot afford to pay $400-500 a piece for handheld Dopplers to use with intermittent auscultation. Electronic fetal monitoring is the perfect example of high-tech, high-cost, low evidence-based care.

Clinical experience. Many doctors and nurses have never used a fetal stethoscope (some do not even know they exist). Some OB’s may have never even heard of intermittent auscultation. Although OB’s seem to be comfortable using a handheld Doppler to listen to the baby’s heart rate during prenatal appointments, many have never had any training or experience in using this technique during labor. As one doula told me, “I have yet to meet an OB or nurse that even knows what a fetoscope is let alone how to use it, and I’ve never seen an OB or nurse use a Doppler outside of prenatal appointments.” Nurses and OB’s are much more comfortable using EFM, since they have probably had a lot of training and experience with it. In summary, as one midwife wrote on her own blog… “You CAN say no to the fetal monitor, but you’ll need to bring your own Doppler—and nurse.”

Lack of leadership from ACOG. In their 2009 practice guidelines for fetal monitoring, ACOG states that “despite the frequency of its use, limitations of EFM include poor interobserver and intraobserver reliability, uncertain efficacy, and a high false-positive rate (pg. 193).” ACOG lists all of the risks of EFM that I have described in this article (increased risk of Cesarean delivery, vacuum/forceps delivery, etc.), and the overall lack of benefits compared to intermittent auscultation. But then it goes on to state that “either option (EFM or intermittent auscultation) is acceptable (pg. 196)” and that “logistically, it may not be feasible to adhere to guidelines for how frequently the heart rate should be auscultated (pg. 196).” The rest of the article focuses on how to conduct EFM. Until ACOG makes a clear statement that intermittent auscultation is preferable to EFM, obstetricians in the U.S. will probably stick with the status quo of EFM—even though the research evidence overwhelmingly supports intermittent auscultation, and this evidence has been around for more than 30 years now. The American College of Nurse Midwives openly disagrees with ACOG and says that intermittent auscultation– not electronic monitoring– should be the preferred method.

Finally, what can I do if I want intermittent auscultation, but it is not offered by my chosen place of birth?

Answer: Check out my interview with Sarah, a first-time mom who was the first woman to receive intermittent auscultation at her hospital!

Have you ever received intermittent auscultation or electronic fetal monitoring? Which one did you have, and what was your experience like?

References:

Association of Women’s Health, Obstetric, and Neonatal Nurses (AWHONN). (2008) “Fetal heart monitoring.”

American Congress of Obstetricians and Gynecologists. (2009). “ACOG Practice Bulletin No. 106: Intrapartum fetal heart rate monitoring: nomenclature, interpretation, and general management principles.” Obstetrics and gynecology 114(1): 192-202.

Alfirevic, Z., D. Devane, et al. (2006). “Continuous cardiotocography (CTG) as a form of electronic fetal monitoring (EFM) for fetal assessment during labour.” Cochrane database of systematic reviews(3): CD006066.

Bailey, R. E. (2009). “Intrapartum fetal monitoring.” Am Fam Physician 80(12): 1388-1396.

Declercq, E. R., C. Sakala, et al. (2007). “Listening to Mothers II: Report of the Second National U.S. Survey of Women’s Childbearing Experiences: Conducted January-February 2006 for Childbirth Connection by Harris Interactive(R) in partnership with Lamaze International.” J Perinat Educ 16(4): 15-17.

Herbst, A. and I. Ingemarsson (1994). “Intermittent versus continuous electronic monitoring in labour: a randomised study.” Br J Obstet Gynaecol 101(8): 663-668.

Nelson, K. B., J. M. Dambrosia, et al. (1996). “Uncertain value of electronic fetal monitoring in predicting cerebral palsy.” N Engl J Med 334(10): 613-618.