Electronic fetal monitoring
Is not necessary for low risk labours

by Ros Goddard, specialist registrar in obstetrics and gynecology in the Royal United Hospital, England

Electronic fetal monitoring with the cardiotocograph is standard practice during labour in most obstetric units in the United Kingdom. The technique was introduced as a screening test in the 1970s in the belief that it would improve the detection of fetal hypoxaemia and reduce cerebral palsy and perinatal mortality, particularly in high risk pregnancies. Early retrospective observational studies supported the view that it was superior to intermittent auscultation using either a Pinard stethoscope or a hand held doppler ultrasound device.  Its use spread rapidly from high risk to low risk pregnancies where the fetus is at least risk from hypoxic events in labour. Was this spread necessary or wise?

By the 1990s systematic reviews of randomized controlled trials of electronic fetal monitoring versus intermittent auscultation during labour had shown no effect on neonatal outcomes such as metabolic acidosis at birth, low Apgar scores or admissions to neonatal intensive care.  An increase in neonatal seizures was seen in the group with intermittent auscultation but no long term increase in neurological problems.
 
Electronic fetal monitoring did, however, have an effect on women in labour. Levels of obstetric intervention augmentation of labour, epidural anaesthesia, instrumental delivery, and caesarean section consistently increased.  Instrumental delivery and caesarean section were even more common when electronic fetal monitoring was not backed up by fetal blood sampling. The impact on the mother and her experience of labour was therefore considerable, without any gain for the baby. In many units this evidence allowed a return to intermittent auscultation, which is less intrusive for the woman. Unfortunately the dramatic increase in litigation in obstetrics has tempered this change, as the cardiotocograph has also become an important legal document.

An admission cardiotocograph was introduced to identify fetuses at risk which needed closer monitoring during labour, allowing those with no signs of distress to be monitored by intermittent auscultation. In their large randomized controlled trial in this week's BMJ Mires et al show that even this brief cardiotocograph on admission has a similar effect in low risk women to the use of the cardiotocograph throughout labour.  The intervention rate increased significantly with no effect on neonatal outcome.

In low risk pregnancies adverse events during labour that affect the development of the baby are rare. Most cases of cerebral palsy have antecedents in the antenatal period,  with only about 10% of cases having an intrapartum cause. The prevalence of perinatal mortality or cerebral palsy from intrapartum causes is about 0.8 per 1000 and 0.1 per 1000 respectively.  Most studies of electronic fetal monitoring were underpowered to detect these rare events and have concentrated on more immediate fetal outcomes. When perinatal mortality was studied no effect was seen. Nevertheless, the cardiotocograph continues to be an important document in many legal cases concerning cerebral palsy.

So the evidence is strongly against the routine use of electronic fetal monitoring. This is further reinforced by the publication last month of the Royal College of Obstetricians and Gynaecologists' guidelines on electronic fetal monitoring, which have been developed with the National Institute for Clinical Excellence.  This important document has brought together all the good evidence on electronic fetal monitoring. There are some important messages, which should affect practice on labour wards throughout Britain.

The chief recommendation is that intermittent auscultation is the most appropriate method of fetal monitoring for women in labour who are low risk. This allows the best compromise between assuring fetal safety and allowing the woman mobility and independence during labour. For auscultation to be successful it needs to be frequent, especially in the second stage of labour, and therefore requires one to one care of the woman. Unfortunately this is an ideal which may be impossible in hard pressed labour wards, where midwives are often in short supply. Ironically, there is good evidence that one to one care alone has a powerful effect on the labouring woman, reducing intervention.  The cardiotocograph can become a surrogate for this best quality care and has a major impact on the caesarean section rate.

If intermittent auscultation identifies a problem or the woman has major risk factors, then electronic fetal monitoring should be used. The main problem then lies in interpreting the cardiotocograph trace. The guidelines address this at length and provide good criteria for identifying suspicious and abnormal traces. Another key recommendation is that all professionals involved in managing labour should have regular, continuing training in interpreting and storing cardiotocographs. This recommendation is in line with three recent Confidential Enquiries into Stillbirths and Deaths in Infancy, which have consistently recognized inadequate interpretation of the cardiotocograph as a prime cause of adverse events. To prevent litigation trusts should act on this recommendation and ensure that such training is available free for all relevant staff.

The guidelines have also looked at other methods of testing fetal well being in early labour and of fetal monitoring, such as fetal pulse oximetry and fetal electrocardiography. These newer tools may be useful as an adjunct to electronic monitoring, but they are no more predictive of adverse outcomes. Research is needed to identify more specific tests of fetal well being that will allow us to identify babies at risk during labour without having a major impact on women. For now, it is important that electronic fetal monitoring should be used appropriately in high risk women and that intermittent auscultation is recognized as a valid form of management for most low risk cases.

Ros Goddard, specialist registrar in obstetrics and gynaecology.
Royal United Hospital, Bath BA1 3NG (ros_goddard@hotmail.com)

1. Royal College of Obstetricians and Gynaecologists. The use of electronic fetal monitoring: the use and interpretation of cardiotocography in intrapartum fetal surveillance. London: RCOG, 2001.
2. Neilson JP. Cardiotocography during labour. BMJ 1993; 306: 347-348[Medline].
3. Grant A. Monitoring the fetus during labour. In: Chalmers I, Enkin M, Keirse MJNC, eds. Effective care in pregnancy and childbirth. Oxford: Oxford University Press, 1989:846-882.
4. Thaker SB, Stroup DF, Chang M. Continuous electronic heart rate monitoring for fetal assessment during labor (Cochrane Review). Cochrane Database Syst Rev 2001;2:CD000063.
5. Grant A, O'Brien N, Joy MT, Hennessy E, MacDonald D. Cerebral palsy among children born during the Dublin randomised trial of intrapartum monitoring. Lancet 1989; 8674: 1233-1236[Medline].
6. Ingemarsson I. Electronic fetal monitoring as a screening test. In: Spencer JAD, Ward RHT, eds. Intrapartum fetal surveillance. London: RCOG Press, 1993:45-52.
7. Mires G, Williams F, Howie P. Randomised controlled trial of cardiotocography versus Doppler auscultation of fetal heart at admission in labour in low risk obstetric population. BMJ 2001; 322: 1457-1462[Abstract/Full Text].
8. Hodnett ED. Caregiver support for women during childbirth. Cochrane Database Syst Rev 2000;2:CD000199.
9. Maternal and Child Health Research Consortium. Confidential enquiry in to stillbirths and deaths in infancy: fourth annual report. London: MCHRC, 1997.
10. Maternal and Child Health Research Consortium. Confidential enquiry in to stillbirths and deaths in infancy: fifth annual report. London: MCHRC, 1998.
11. Maternal and Child Health Research Consortium. Confidential enquiry in to stillbirths and deaths in infancy: seventh annual report. London: MCHRC, 2001.

Electronic Fetal Monitoring (EFM)
If recent studies do not support the routine use of EFM, why is it still so widely used? First, because many nurses and physicians have not been trained in intermittent auscultation. Second, some believe that EFM might still be a valuable assessment tool with better guidelines for interpreting tracings and making management decisions, even though studies comparing the ability of experts to agree on the interpretation of an EFM tracing have shown poor interpreter reliability.  Third, physicians may fear that they will be vulnerable to malpractice lawsuits if they do not use EFM. The impact of changing to intermittent monitoring on malpractice claims is unknown. Fourth, many hospitals are not adequately staffed to do intermittent auscultation. In one study, a university hospital center attempted to use intermittent auscultation as the primary method of monitoring without increasing the number of staff. Auscultation was only successfully completed in 31 of 862 patients in labor with viable fetuses.
- American Academy of Family Physicians, May 1, 1999

A conversation I had a few years ago with Dr. John Ott, the author of the book Health and Light, shed some light on non-advancing labor where the mother and/or baby is hooked up to a monitor. Dr. Ott's research in the color spectrum wavelengths led to a curiosity about the effects of electrical fields on the human body. His work led to the first commercially available full-spectrum shielded fluorescent lighting. He told me that susceptible persons are greatly weakened by artificial energy fields.

Dr. Ott predicted that the number of cesareans would increase in hospitals using fetal monitors. But his reasons were different than most would think. He claimed that when a maternal or fetal monitor is hooked up, its energy field makes muscles weak for both baby and mother. And of course, the uterus is a muscle. Add to this all the electronic equipment in the typical delivery room, plus all the voltage-carrying conduits in the hospital.
- Judy Ritchie,  Autumn 1999

The issue of whether EFM reduces brain damage to the offspring received its biggest surprise with the publication of a randomized clinical trial which assessed the neurological development at 18 months of age of 2 samples of children, one group born prematurely whose heart rates were monitored electronically during birth and compared with the other group of children born prematurely whose heart rates during birth were monitored by auscultation. The incidence of cerebral palsy was 20% in the EFM group and 8% in the group that was monitored by auscultation. That the use of EFM should possibly increase the incidence of cerebral palsy may be the result of birth attendants focusing on the monitor rather than the overall condition of the woman and baby. The authors admitted to being unprepared for such a negative finding and a flurry of letters in subsequent issues of the same journal indicated that many other resist data which is against their beliefs....The fact that the cerebral palsy rates have remained the same for the past 30 years in spite of widespread EFM is further evidence of the lack of efficacy of EFM to reduce neurological sequelae. These results echo those of the other randomized controlled trials: There is no scientific evidence that routine EFM during labour improves the condition of the baby at birth or reduces the possibility of brain damage.
- Marsden Wagner, MD, Pursuing the Birth Machine, Ace Graphics 1994

Doctors tell us that EFM protects against malpractice suits or hospitals have too few nurses to auscultate often enough (Ob Gyn News 1988). The malpractice argument rests on beliefs that tracings are valuable courtroom evidence and that not using EFM renders doctors liable because it is standard practice. As to the first, Sandmire (Obstet Gynecol 1990) trenchantly observes that a tracing "leaves a permanent record for hindsight interpretation by expert witnesses" who will claim that mild deviations indicate fetal distress. As for the liability issue, Gilfax (Am J Law Medicine 1984) reviewed the law pertaining to EFM and informed consent and concluded that using auscultation over EFM did not render a doctor liable because of the abundant evidence that auscultation is equally good. Indeed, Gilfix continued, informed consent demands that women be informed of risks and benefits of proposed tests and treatments, which would mean a duty to inform women that EFM has not been shown to improve outcomes but increases operative delivery rates. Finally, "too few nurses to auscultate" really means too few nurses to provide optimum care. Gilfix thinks doctors may be obliged to inform women of this too.

Meanwhile, what about "first do no harm"? Both of these defenses of EFM are predicated on benefits to doctors and hospitals at the expense of mothers and babies.

Judith Lumley (Birth 1982), quoting J.B. McKinley, paints yet a darker picture of the forces driving EFM: "The success of an innovation has little to do with its intrinsic worth...but is dependent upon the power of the interests that sponsor and maintain it....The power of such interests is also evident in their ability to impede the development of alternative practices...that could conceivably threaten an activity in which there is already considerable investment. The "need for universal EFM legitimates so many other contentious decisions on the place, style and management of labor that it will not be discarded in favor of [auscultation] but only displaced when another new, equally unevaluated procedure arrives on the obstetric scene." This would explain why only one study has looked at whether auscultation was feasible in a big, busy unit--finding, by the way, that it was (Sandmire).
- Henci Goer, Obstetric Myths Versus Research Realities, Bergin & Garvey, 1995