The medical and legal risks of the electronic fetal monitor.

• Author: Lent, Margaret

Electronic fetal heart monitoring (EFM) is the most widely used method of monitoring the fetal heartbeat for possible signs of distress during delivery. Soon after its development in the 1960s, EFM replaced intermittent auscultation as the standard of care in the obstetrical community. However, Margaret Lent argues that the widespread use of EFM is both medically and legally unsound Lent points to a series of clinical trials that demonstrate that EFM does not reduce fetal mortality, morbidity, or cerebral palsy rates. These studies suggest that EFM has a very high false positive rate, and that EFM usage correlates strongly with a rise in cesarean section rates. Similarly, EFM provides no protection in the courtroom. Though obstetricians believe that they should use EFM because its status as the standard of care will protect them from liability, Lent argues that it may in fact expose them to liability given its failings. Instead, she argues that auscultation is equally, if not more, safe and effective, and is more likely to protect physicians from liability. Lent concludes that obstetricians have an obligation to their patients and to themselves to adopt auscultation as the new standard of care.

The medical profession depends on the latest medical technologies to provide top quality care and to extend that care to a greater pool of patients. This dependence is all well and good where the method, drag, or device is tested in clinical trials that establish its efficacy and safety. But what happens when new technology diffuses rapidly into mainstream medicine well before it has been adequately tested?

The story of electronic fetal heart monitoring (EFM) reveals the problems posed to physicians and patients by the hasty acceptance of relatively unproven devices and techniques. When EFM was introduced in the 1960s, enthusiastic advocates promised that by enabling the continuous, electronic monitoring of the fetal heart rate during labor and delivery, EFM would enable physicians to detect dangerous heart rate patterns and to intervene more promptly than with intermittent auscultation, the long-employed technique of periodically monitoring fetal heart rate with an obstetrical stethoscope. Thus, announced EFM proponents, the device would reduce rates of neonatal illness and death. Based on these promises, EFM became the predominant form of fetal heart monitoring by the mid- to late 1970s.(1) However, experts now conclude that these promises remain unfulfilled and that EFM is, at best, a "disappointing story."(2) In the twenty-five years of its almost ubiquitous use, no randomized controlled trial has demonstrated that electronic monitoring does a better job of saving babies or improving infant health than intermittent auscultation.(3) Moreover, studies indicate that the inaccuracy of the technique prompts unnecessary interventions and contributes to the nation's excessively high rate of cesarean delivery, a major surgical procedure which places mother and infant at greater risk of injury and death than noncesarean delivery.(4) Despite the increased risks, the device remains employed in nearly all American delivery rooms. Continued high use of EFM is often attributed to physician concerns about medical malpractice liability and professional inertia. As one EFM critic has observed: "[Doctors] talk about [abandoning EFM] at conferences and at [medical] rounds and listen intently and all of that, but it's not measurable in terms of changes in behavior. Everybody's waiting for the next person to get brave."(5)

A quarter century of failure in clinical trials and striking new evidence documenting EFM's imprecision indicate that now is the ideal time for the obstetrical profession to "get brave." To ensure the safety of their patients and to preserve national confidence in the profession, obstetricians must abandon EFM and adopt safer, more effective monitoring methods such as intermittent auscultation. Close analysis of the legal and medical consequences of the use of EFM reveals that obstetricians have little to fear in discontinuing use of the technique. Not only is EFM an inferior diagnostic tool in the delivery room, but it fails to offer the courtroom protection obstetricians suppose. Moreover, a physician's decision to return to safer,, effective methods such as auscultation should not expose her to liability. In short, there are no excuses left to defend the continued use of EFM.

This note will first examine the medical inefficacy of EFM, including its poor performance in controlled trials, production of questionable data, potential to exacerbate patient dissatisfaction, high cost, and link to increased cesarean rates. Then it will analyze the implications of EFM use in a legal context, applying tort law's standard of care analysis to the technique and comparing obstetricians' perception of EFM's role in malpractice litigation to its actual function in a lawsuit. Finally, the note proposes that obstetricians create a new standard of care through definitive professional practice guidelines and consensus conferences, and recommends that obstetricians abandon EFM for intermittent auscultation.(6)

1. ELECTRONIC FETAL MONITORING IN THEORY AND PRACTICE

   1. History and Theory Behind Fetal Heart Monitoring

      For over 100 years, physicians have employed some form of fetal heart monitoring during the management of labor.(7) The purpose of fetal heart monitoring is to detect abnormal fetal heart rates, which indicate stress on the fetus. Not all stresses are considered a threat to the fetus.(8) Only when physicians find evidence of "fetal distress"--where the fetus appears incapable of handling stress to the heart--do they intervene to help the fetus.

      Historically, one major cause of "fetal distress" indicated by fetal heart monitoring is deprivation of oxygen to the fetus. This condition, known as fetal asphyxia or hypoxia, results from poorly oxygenated blood in the mother or by an obstruction.(9) Fetal asphyxia or hypoxia may cause fetal neurological disorders, such as cerebral palsy, or even death. As such, intervention is required when physicians interpret the presence of fetal asphyxia or hypoxia.

      Before the development of EFM, fetal heart rates were monitored through intermittent auscultation, the periodic monitoring of fetal heartbeats by stethoscope.(10) In 1960, the same presumption that generated the development of auscultation over 100 years ago--that early detection of abnormal heart rates indicating distress enabled physicians to prevent infant death and neurological disorders--inspired the development of EFM.(11) EFM improved upon auscultation, according to founders and enthusiasts, because continuous electronic monitoring allowed clinicians not only to detect abnormal heart rate but also abnormal heart rate patterns suggesting hypoxia and asphyxia.(12) By identifying fetal heart rate patterns that indicated fetal distress, EFM would alert clinicians to potential problems, enabling them to intervene more quickly and to prevent more fetal deaths and irreversible brain injuries than could be prevented with auscultation.(13)

   2. Mechanics of the EFM Method

      There are two EFM methods. The external method employs two wide belts which strap around a mother's abdomen, holding the monitor and electronic sensors in place. In the more invasive and more common internal method, an electrode is inserted through the vagina and attached to the fetal scalp.(14) The monitor generates a continuous paper tape that traces both the fetal heart rate and the mother's contractions, projecting this data upon a video monitor attached to the unit. Alarm sensors in the EFM device sound if the heart rate dips below or rises above "normal range."(15) In larger obstetrical units, clinicians typically monitor several EFM devices simultaneously from a "floor monitor" centrally situated within a labor and delivery unit.

      In analyzing an EFM tracing for signs of asphyxia or hypoxia, physicians look for two things. First, they scrutinize heart rate patterns for multiple late decelerations--abnormal patterns involving a rapid fall in fetal heart rate.(16) Occasional or intermittent late decelerations are not uncommon during labor. But when they become persistent or severe, clinicians may determine that the fetus is in distress.(17) Second, clinicians interpreting EFM tracings look for "beat-to-beat variability"--moment-to-moment changes in fetal heart rate which are apparent in electronic measurements between heartbeats.(18) The tracing of a healthy fetal heartbeat demonstrates "short-term" variability-fairly rapid changes between heartbeats. Lack of short-term variability may indicate a range of normal fetal states, including sleep or the effects of medication administered to the mother.(19) Lack of variability may also have a more ominous significance, suggesting the beginnings of brain damage caused by hypoxia.(20) Confronting a pattern that may indicate one of two polar opposite conditions--a healthy fetus at rest or fetal distress--physicians often intervene.(21) Such intervention may take the form of an attempt to remove the cause of the perceived distress, or, more commonly, delivery via cesarean section.(22)

   3. Expansion of EFM

      EFM began its rapid diffusion into obstetrical practice in the early 1970s, soon after its development.(23) It was widely adopted for a number of reasons. Physicians perceived hypoxia as an important cause of neonatal mortality and morbidity,(24) and many expected that the technique would dramatically reduce the frequency of fetal death, cerebral palsy and other neurological disorders.(25) The technique appeared to offer benefits to physicians. In particular, it appeared easier to learn than auscultation, which obstetricians perceived as imperfect.(26) The device's fortuitous timing further augmented its already warm reception. EFM arrived upon the obstetrical scene during a period when the nation was poised to...