Must read!

"EFM as a Public Health Screening Program: The Arithmetic of Failure"
                                    by Dr David Grimes

NOTE: I have a PDF version that i can email to anyone who wants to read the entire paper.

Electronic Fetal Monitoring as a Public Health Screening Program:
The Arithmetic of Failure

David A. Grimes, MD, and Jeffrey F. Peipert, MD, PhD

VOL. 116, NO. 6, DECEMBER 2010 OBSTETRICS & GYNECOLOGY 1397

From FHI, Research Triangle Park, North Carolina; the Department of Obstetrics and Gynecology, University of North Carolina School of Medicine, Chapel Hill, North Carolina; and the Division of Clinical Research and the Department of Obstetrics and Gynecology, Washington University in St Louis School of Medicine, St. Louis, Missouri. Corresponding author: David A. Grimes, MD, FHI, PO Box 13950, Research Triangle Park, NC 27709; e-mail: dgrimes@fhi.org.

Abstract

Electronic fetal monitoring has failed as a public health screening program. Nevertheless, most of the four million low-risk women giving birth in the United States each year continue to undergo this screening. The failure of this program should have been anticipated and thus avoided had the accepted principles of screening been considered before its introduction. All screening tests have poor positive predictive value when searching for rare conditions such as fetal death in labor or cerebral palsy. This problem is aggravated when the screening test does not have good validity as is the case with electronic fetal monitoring. Because of low-prevalence target conditions and mediocre validity, the positive predictive value of electronic fetal monitoring for fetal death in labor or cerebral palsy is near zero. Stated alternatively, almost every positive test result is wrong. To avoid such costly errors in the future, the prerequisites for any screening program must be fulfilled before the program is begun.

*A new drug must present a rigorous set of experimental data before it is licensed for use, and until it is licensed, patients are not permitted to obtain it. The same rigor should apply to medical screening.” [1]

{* I paraphrased just this introductory sentence for clarity – all the rest of document is original text only}

Electronic fetal monitoring has failed as a public health screening program. Randomized controlled trials of electronic fetal monitoring compared with intermittent auscultation reveal that electronic fetal monitoring statistically significantly increases instrumental and cesarean deliveries for women but provides no long-term benefits for children. [2]

Clinicians, too, have suffered indirectly because of the epidemic of litigation and “expert” testimony that electronic fetal monitoring has spawned about fetal heart-rate tracings. [3] Sadly, the failure of electronic fetal monitoring could have, and should have, been predicted and thus avoided.

The fundamental error made decades ago was viewing electronic fetal monitoring as an obstetric technology for an individual woman, and not as the national public health screening program that it is.

This error was compounded by naïvete´ about screening principles and exaggeration of the value of positive results. [4]

What Is Screening?

Screening is the testing of large numbers of apparently well persons to identify those at increased risk of disease. Because screening is done among asymptomatic persons, the ethical burden on those ordering the tests is higher than when performing tests on ill persons. This is because false-positive results of screening can deprive persons of their perceived health, prompt unnecessary diagnostic tests and procedures with their attendant morbidity, and waste money and other resources.5 Hence, stringent requirements must be met before a screening program starts. This did not happen with electronic fetal monitoring.1 We will restrict our commentary to the usual use of electronic fetal monitoring as a screening test in asymptomatic women; when used in women with signs or symptoms suggestive of adverse outcomes (eg, meconium-stained amniotic fluid), electronic fetal monitoring could be considered a diagnostic test.

Avoiding …. Mistakes

Electronic fetal monitoring during labor is not recommended for women at low risk. [10 , 11, 12] Despite these consistent recommendations on both sides of the Atlantic Ocean, approximately 3.4 million US women at low risk are screened annually with electronic fetal monitoring.[10]

{Note by FG: Situations in which physicians continue to order or perform procedures that lacks a scientific foundation or are in direct opposition to the best evidenced is called “physician preference” and describes a choice made by the doctor to ignore professional sources due to some personal benefit to themselves, including a perceived advantage in case there is a lawsuit. This represents a process of asymmetrical risk-shifting, cost-shifting and at times, blame-shifting, in which these burdens are shifted from the physician to the mother and/or the unborn baby.

Nonetheless, it still is a personal and not a professional or scientifically-based choice that is almost always done without first informing the patient and obtaining the patient’s consent. This means the physician did not acknowledge that the recommended treatment reflected his or her personal choice and therefore was not evidence-based care but 19^th century “authority-based” medicine predicated on the individual opinion of that particular doctor at that particular time.}

Aside from the wasted money and time, electronic fetal monitoring increases operative deliveries, yet offers no lasting benefit to children. [2,10] Electronic fetal monitoring harms women; compared with vaginal births, cesarean deliveries are associated with a statistically significant increase in uncommon but serious complications, including cardiac arrest …. hemorrhage requiring hysterectomy, venous thromboembolism, and major infection. Cesarean deliveries have also been linked with placenta accreta in later pregnancies.

Electronic fetal monitoring should be reserved for women at increased risk of adverse outcomes [11] in whom screening will perform better. As the frequency increases, the positive predictive value will rise. However, for rare outcomes, the improvement is negligible. For example, if the risk of fetal death in labor were 10-fold higher (500 per 100,000) than that in Table 3, the positive predictive value would be 285/ 31,130, or 1%, assuming the same sensitivity and specificity.

With a 10-fold increase in the frequency of intrapartum death, 99% of positive tests are still wrong, illustrating the limited value of such screening. This is an inescapable, but little understood, principle of screening.

More common but less serious, fetal acidemia at birth may provide the most charitable assessment of electronic fetal monitoring. In a large randomized controlled trial with a frequency of fetal acidemia at birth (umbilical cord artery pH less than 7.15) of 10%,

nonreassuring fetal heart rate patterns had a positive predictive value of 37%.[13] Even for this common outcome, most positive tests were wrong.

Final Conclusions:

Screening is a public health strategy that transcends clinical disciplines. Whether the target condition is neural tube defect, scoliosis, osteoporosis, abdominal aortic aneurysm, or cerebral palsy, accepted criteria for mounting a screening program must be satisfied before screening is begun. [5,12] Paradoxically, few clinicians who routinely use electronic fetal monitoring in labor would use a pregnancy test (or home smoke detector) that is wrong almost every time a positive signal appears. [4] Careful evaluation of a screening test must be done before, not after, a program has been widely adopted and disseminated. [1] By then, the damage has been done.

REFERENCES

1. Law M. Screening without evidence of efficacy. BMJ 2004;328: 301–2.

2. Alfirevic Z, Devane D, Gyte GM. Continuous cardiotocography (CTG) as a form of electronic fetal monitoring (EFM) for fetal assessment during labour. The Cochrane Database of Systematic Reviews 2006, Issue 3. Art. No.: CD006066. DOI: 10.1002/14651858.CD006066.

3. Lent M. The medical and legal risks of the electronic fetal monitor. Stanford Law Rev 1999;51:807–37.

4. Steurer J, Fischer JE, Bachmann LM, Koller M, ter Riet G. Communicating accuracy of tests to general practitioners: a controlled study. BMJ 2002;324:824 – 6.

5. Grimes DA, Schulz KF. Uses and abuses of screening tests. Lancet 2002;359:881– 4.

6. Martin DH, Cammarata C, Van Der Pol B, Jones RB, Quinn TC, Gaydos CA, et al. Multicenter evaluation of AMPLICOR and automated COBAS AMPLICOR CT/NG tests for Neisseria gonorrhoeae. J Clin Microbiol 2000;38:3544 –9.

7. Larma JD, Silva AM, Holcroft CJ, Thompson RE, Donohue PK, Graham EM. Intrapartum electronic fetal heart rate monitoring and the identification of metabolic acidosis and hypoxic–ischemic encephalopathy. Am J Obstet Gynecol 2007;197:301.e1– 8.

8. Walsh CA, McMenamin MB, Foley ME, Daly SF, Robson MS, Geary MP. Trends in intrapartum fetal death, 1979 –2003. Am J Obstet Gynecol 2008;198:47.e1–7.

9. Hirtz D, Thurman DJ, Gwinn-Hardy K, Mohamed M, Chaudhuri AR, Zalutsky R. How common are the ‘common’ neurologic disorders? Neurology 2007;68:326 –37.

10. Intrapartum fetal heart rate monitoring: nomenclature, interpretation, and general management principles. ACOG Practice Bulletin No. 106. American College of Obstetricians and Gynecologists. Obstet Gynecol 2009;114:192–202.

11. National Collaborating Centre for Women’s and Children’s Health. Intrapartum care. Care of healthy women and their babies during childbirth.

Available at: www.nice.org.uk/nice-media/live/11837/36275/36275.pdf Retrieved June 4, 2010.

12. US Preventive Services Task Force. Guide to clinical preventive services. 2nd ed. Baltimore (MD): Williams & Wilkins; 1996.

13. Vintzileos AM, Nochimson DJ, Antsaklis A, Varvarigos I, Guzman ER, Knuppel RA. Comparison of intrapartum electronic fetal heart rate monitoring versus intermittent auscultation in detecting fetal acidemia at birth. Am J Obstet Gynecol1995;173:1021– 4.

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