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The Role of Interpretation – ACOG Refines Fetal Heart Rate Monitoring Guidelines

I remember when I was pregnant with my first.  The CNM I hired worked at multiple hospitals, so my husband and I toured each one to get a feel for each hospital’s standard policies and procedures.  A few people I knew questioned why we were bothering doing this since, aren’t all hospitals the same?  While I was expecting some differences, I was really surprised with what I found.  The standard procedures of the three hospitals we toured varied greatly – everything from the use of telemetry (wireless fetal) monitoring to how much bonding time a mom and baby were permitted before baby was whisked away for mandatory hospital procedures to where babies slept at night and whether babies were routinely given sugar water, formula or a pacifier.  I came away realizing how important it is to carefully screen which hospital you chose as well as your OB/midwife and the L&D nurse who will be caring for you during your stay at the hospital.

This June 22, 2009 press release illustrates ACOG’s (The American College of Obstetricians and Gynecologists’) efforts to help standardize the care women receive from OBs.  Specifically, they wish to stabilize the variability in fetal heart rate interpretations which could considerably impact the frequency of the “fetal distress” diagnosis.

EFM refers to external fetal monitoring which most women know as the belt laboring women wear that measures the baby’s heart rate and is connected to a machine which produces a strip of the baby’s heart rate as well as mom’s contractions.

I found these quotes of particular interest (emphasis is mine). 

"Since 1980, the use of EFM has grown dramatically, from being used on 45% of pregnant women in labor to 85% in 2002," says George A. Macones, MD, who headed the development of the ACOG document. "Although EFM is the most common obstetric procedure today, unfortunately it hasn’t reduced perinatal mortality or the risk of cerebral palsy. In fact, the rate of cerebral palsy has essentially remained the same since World War II despite fetal monitoring and all of our advancements in treatments and interventions."

"Our goal with the ACOG guidelines was to define existing terminology and narrow definitions and categories so that everyone is on the same page," says Dr. Macones. One of the problems with FHR tracings is the variability in how they’re interpreted by different people. The ACOG guidelines highlight a case in which four obstetricians examined 50 FHR tracings; they agreed in only 22% of the cases. Two months later, these four physicians reevaluated the same 50 FHR tracings, and they changed their interpretations on nearly one out of every five tracings.

A meta-analysis study shows that although EFM reduced the risk of neonatal seizures, there is still an unrealistic expectation that a nonreassuring FHR can predict the risk of a baby being born with cerebral palsy. The false-positive rate of EFM for predicting cerebral palsy is greater than 99%. This means that out of 1,000 fetuses with nonreassuring readings, only one or two will actually develop cerebral palsy. The guidelines state that women in labor who have high-risk conditions such as preeclampsia, type 1 diabetes, or suspected fetal growth restriction should be monitored continuously during labor.

Note that VBAC is not listed under “high-risk conditions” that “should be monitored continuously during labor.”  Also, with a 99% false positive rate for cerebral palsy, I wonder how effective EFM is for detecting uterine rupture.

Here is the link, ACOG Refines Fetal Heart Rate Monitoring Guidelines, but since I’ve linked to ACOG press releases that then disappeared, I’m going to include the entire press release below.

For Release:
June 22, 2009

ACOG Refines Fetal Heart Rate Monitoring Guidelines

Washington, DC — Refinements of the definitions, classifications, and interpretations of fetal heart rate (FHR) monitoring methods were issued today in new guidelines released by The American College of Obstetricians and Gynecologists (ACOG). The objective of the guidelines is to reduce the inconsistent use of common terminology and the wide variability that sometimes occurs in FHR interpretations. ACOG’s Practice Bulletin, published in the July 2009 issue of Obstetrics & Gynecology, supports the recommendations of the Eunice Kennedy Shriver National Institute of Child and Health Development workshop* on electronic fetal monitoring (EFM) held in April 2008.

The intent of FHR monitoring is to help keep an eye on the status of the fetus during labor and intervene if necessary. There are two main FHR monitoring methods. The most commonly used method is EFM, which detects the fetal heart rate and the length of uterine contractions and the time between them. EFM allows physicians and nurses to measure the response of the fetal heart rate to uterine contractions. A lesser-used method is manual auscultation, which employs either a small handheld Doppler device or a fetoscope (similar to a stethoscope). A normal fetal heart varies between 110 and 160 beats per minute. A heart rate that doesn’t vary or is too low or too high may signal a potential problem with the fetus.

"Since 1980, the use of EFM has grown dramatically, from being used on 45% of pregnant women in labor to 85% in 2002," says George A. Macones, MD, who headed the development of the ACOG document. "Although EFM is the most common obstetric procedure today, unfortunately it hasn’t reduced perinatal mortality or the risk of cerebral palsy. In fact, the rate of cerebral palsy has essentially remained the same since World War II despite fetal monitoring and all of our advancements in treatments and interventions."

One notable update in the guidelines is the three-tier classification system for FHR tracings (print-outs of the fetal heart rate). Category 1 FHR tracings are considered normal and no specific action is required. Category 2 tracings are considered indeterminate. This category requires evaluation and surveillance and possibly other tests to ensure fetal well-being. Category 3 tracings are considered abnormal and require prompt evaluation, according to ACOG. An abnormal FHR reading may require providing oxygen to the pregnant woman, changing the woman’s position, discontinuing labor stimulation, or treating maternal hypotension, among other things. If the tracings do not return to normal, the fetus should be delivered.

"Our goal with the ACOG guidelines was to define existing terminology and narrow definitions and categories so that everyone is on the same page," says Dr. Macones. One of the problems with FHR tracings is the variability in how they’re interpreted by different people. The ACOG guidelines highlight a case in which four obstetricians examined 50 FHR tracings; they agreed in only 22% of the cases. Two months later, these four physicians reevaluated the same 50 FHR tracings, and they changed their interpretations on nearly one out of every five tracings.

A meta-analysis study shows that although EFM reduced the risk of neonatal seizures, there is still an unrealistic expectation that a nonreassuring FHR can predict the risk of a baby being born with cerebral palsy. The false-positive rate of EFM for predicting cerebral palsy is greater than 99%. This means that out of 1,000 fetuses with nonreassuring readings, only one or two will actually develop cerebral palsy. The guidelines state that women in labor who have high-risk conditions such as preeclampsia, type 1 diabetes, or suspected fetal growth restriction should be monitored continuously during labor.

Practice Bulletin #106, "Intrapartum Fetal Heart Rate Monitoring: Nomenclature, Interpretation, and General Management Principles," is published in the July 2009 issue of Obstetrics & Gynecology.

* In 2008, The Eunice Kennedy Shriver National Institute of Child Health and Human Development partnered with ACOG and the Society for Maternal-Fetal Medicine to sponsor a workshop focused on EFM.

# # #

The American College of Obstetricians and Gynecologists (ACOG) is the nation’s leading group of physicians providing health care for women. As a private, voluntary, nonprofit membership organization, ACOG: strongly advocates for quality health care for women; maintains the highest standards of clinical practice and continuing education of its members; promotes patient education; and increases awareness among its members and the public of the changing issues facing women’s health care.

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5 comments to The Role of Interpretation – ACOG Refines Fetal Heart Rate Monitoring Guidelines

  • [...] they are seeing!!” [That may be what Pinky was referring to in this post. And fwiw, here is one post and another post on ACOG's refining fetal heartrate monitoring guidelines.] The second post has [...]

  • Jenn

    Very interesting! Thank you for this incredibly resource heavy website. For that, here’s the updated link to the ACOG publication:

    http://www.acog.org/About_ACOG/News_Room/News_Releases/2009/ACOG_Refines_Fetal_Heart_Rate_Monitoring_Guidelines

    I thought I had found an article here about the rate of uterine rupture as compared to other obstetrical emergencies in tabular form to compare the rate and maternal and neonetal risk of each, but I am unable to find it now. Do you have that information?

    Thank you!

    • Jen Kamel

      Hi Jenn!

      Thanks for the link update. ACOG updated their website a couple years ago so many of the older links I provide here no longer work.

      I believe the chart you are looking for can be found in an article written by two OBs protesting a VBAC ban at their local rural hospital.

      I’m sure you already know, but for the benefit of future readers, I want to point out that the incidence of obstetrical complications does not necessarily reflect the rates of infant or maternal morbidity/mortality. Take placeta accreta which I talk about quite a bit. The risk is very low for a first time mom (less than 0.5%), but increases with each subsequent cesarean. The risk of maternal mortality for accreta has been reported around 7-8%. That is significant.

      If you want the latest and greatest information on VBAC, I recommend you check out the Guise 2010 Evidence Report, the National Institutes of Health’s VBAC Statement, as well as the many presentation videos from the 2010 NIH VBAC Conference. You can access all of these resources here.

      Warmly,

      Jen

  • Jenn

    Thank you! Oh yes I know about placenta accreta. I am in the situation where my first c-section was medically necessary (severe pre-eclampsia/beginning HELLP) but the hospital/OB was very anti-vbac, so I had to change both to find a vbac friendly environment, but my husband picked up from the previous environment that vbac’s are dangerous and my having to change doctors and hospital makes him nervous. Outlining the risks of other things that can go wrong during any vaginal delivery makes uterine rupture not stand out so much as the worst thing in the world or a reason not to try for a vbac.
    I do have the NIH statement on hand, and also the Department of heath and human services evidence report which gathered the background evidence for the NIH conference – actually I didn’t see it on your resource website, so here that is as well (though I’m sure it’s in your stash somewhere!). I haven’t made it through the whole report yet (400 pages) but what I have read is really interesting.

    http://www.ahrq.gov/downloads/pub/evidence/pdf/vbacup/vbacup.pdf

    Thank you again!

  • Increíble Web .Sigue adelante con este excelente trabajo.
    Presenta un punto de vista realmente excelente sobre el tema y los mensajes son muy acertados.
    Simplemente decir que estoy feliz por haber visto esta Página web
    Seguramente tienes el mejor sitio de internet sobre el tema.

    Muchas gracias :-)