Electronic fetal heart rate monitoring: a story of survival.

The ubiquity of electronic fetal heart rate monitoring (EFM) represents a striking discordance between results of randomized, controlled trials and clinical use. Doctors Banta and Thacker (1) have used EFM as an example of the introduction of a technology into medical care before proofs of efficacy, and their article implies how difficult it is to reverse such a use after it has gained decades of momentum. Their paper is an interesting historical and (particularly) personal insight into the process of technology assessment, and obstetricians should be delighted at their inclusion in such pioneering work. The authors’ thesis regarding the use of monitoring (little or no proven efficacy) and its hazards (mainly increased operative deliveries, although this is given little attention in their paper) is in stark contrast to the continuing popularity of the technique. The use of electronic fetal heart rate monitoring is generally quoted as 80% in North America, but it is probable that almost all pregnant mothers have at least some EFM either before or during labor. Why this discrepancy? The almost universal use of EFM in the face of apparent unproven usefulness and potential risk is unlikely to be a medical conspiracy. If market forces drive its popularity, it is not because of profits pouring into the pockets of MDs and RNs, that is, those who are most directly concerned with the application of monitors and their interpretation. There is no additional professional fee to the MD for fetal heart rate (FHR) interpretation in labor. Is it fear? That is fear of not using EFM because it is the “standard of professional care”? I doubt this because national bodies, including the American College of Obstetricians and Gynecologists, the Royal College of Obstetricians and Gynaecologists of Canada, and the U.S. Preventive Services Task Force, have all given their imprimatur to “intermittent monitoring,” whether this be by auscultation or EFM. Thus, EFM is one standard of care but not the only one. Is it nursing economics? That is, the fact that in the absence of continuous EFM, the hospital would have to attempt to provide more one-on-one nursing, particularly during the late active phase of the first stage and second stage of labor (2). This could be a motivation for hospitals, but it is not the motivating factor for MDs or RNs. My belief is that the interpreters of the randomized, controlled trials have failed to convince the providers of obstetric care of absent efficacy for several reasons. First, it is counter-intuitive to believe that auscultation is better than EFM in that the data obtained with the former mode is only a fraction of that obtained electronically. Second, it has never been shown that auscultation of the fetal heart, or counting the average heart rate during labor, is any better than doing nothing at all. In fact, in an analysis of auscultated FHR data from nearly 25,000 labors resulting in a single live birth or fresh stillbirth, it was concluded that “No reliable single auscultatory indicator of fetal distress exists in terms of fetal heart rate, save in an extreme degree” (3). The “extreme degree” referred to includes standard deviation of auscultated counts, maximum drop from average FHR, lowest FHR recorded, and number of consecutive drops. Calculation of such indices required a computerized database. There are some interesting slips of the tongue from the official bodies, which are so anxious to see RCTs before approving obstetric technologies but turn a blind eye to the complete absence of any studies of efficacy of auscultation. The U.S. Preventive SerAddress correspondence to: J. T. Parer, MD, PhD, Department of Obstetrics, Gynecology and Reproductive Sciences, Box 0550, University of California San Francisco, San Francisco, CA 94143-0550. Volume 58, Number 9 OBSTETRICAL AND GYNECOLOGICAL SURVEY Copyright © 2003 by Lippincott Williams & Wilkins, Inc.