Electronic Fetal Monitoring

Researchers at the Federal Centers for Disease Control and Prevention in Atlanta said a review of the most significant controlled studies of the effectiveness and safety of electronic fetal monitoring indicated that routine use of the procedure had no measurable effect on death or illness of infants or mothers.

But they said electronic monitoring was associated with a higher rate of Cesarean deliveries, which increases surgical risks to mothers.

References

Albers, Leah and C. J. Krulewitch. 1993. "Electronic fetal monitoring in the United States in the 1980s." Obstetrics & Gynecology 82:8-10.
OBJECTIVE: To measure the frequency with which electronic fetal monitoring was used for childbirth in United States hospitals in the 1980s and to examine variation in use according to risk factors at labor onset. METHODS: Two data sets from the National Center for Health Statistics (the 1980 National Natality Survey and the 1988 National Maternal and Infant Health Survey) were used to generate proportional frequencies for electronic fetal monitoring use. These data files are based on representative samples of live births (9941 and 9953, respectively) drawn by probability methods from the entire country during a calendar year. Consistency in the sampling methods and questionnaire procedures, and use of sampling weights, permitted national estimates to be generated. RESULTS: Use of electronic fetal monitoring increased from 44.6% of live births in 1980 to 62.2% in 1988. In both time periods, low-risk women received monitoring more frequently than did women with risk indicators. Use grew by 64% in low-risk women (from 46.5% in 1980 to 76.3% in 1988) but only by 32% in women with risk conditions at labor onset (from 42.6% in 1980 to 56.2% in 1988). CONCLUSIONS: Use of electronic fetal monitoring increased during the 1980s, disproportionately so for low-risk women. This trend raises questions about the efficacy of monitoring for improving pregnancy outcomes.

Albers, Leah L. and D. A. Savitz. 1991. "Hospital setting for birth and use of medical procedures in low-risk women." Journal of Nurse-Midwifery 36:327-33.
This study examined the use of selected medical procedures in low-risk women during childbirth. Data from the 1980 National Natality Survey merged with an American Hospital Association annual survey for the same year were used to assess the frequency with which low-risk women in the United States received certain childbirth procedures and to determine whether their use varied by the hospital setting for birth. Stratified analysis was used to assess the relation of hospital level for delivery with the use of electronic fetal monitoring, labor induction, and primary cesarean delivery in low-risk women, with control for potential confounding factors. As the level of available perinatal technology increased, the use of these procedures increased. Results of the study suggest that low-risk women may have received excess interventions and confirm the need for further examination of care procedures for this group.

Daniels, S. M. and N. Boehm. 1991. "Auscultated fetal heart rate accelerations. An alternative to the nonstress test." Journal of Nurse Midwifery 36:88-94.
This nonexperimental, descriptive correlational study was conducted o determine whether a significant difference exists between the results of an electronically monitored nonstress test (NST) and those of auscultation for single fetal heart rate acceleration, the auscultated acceleration test (AAT). Of 130 NSTs, both the NST and he AAT were reactive in 105 cases and both were nonreactive in seven cases. Eighteen nonreactive AATs went on to have reactive NSTs (72.00% false-positive rate). There were no reactive AATs that went on to have nonreactive NSTs (0% false-negative rate). Various recommendations are made for future research in an attempt to decrease the false-positive rate. The McNemar's test for data analysis used in previous research indicated that there was a significant difference between the two tests. However, the sensitivity (100%) and specificity (85.37%) of the AAT indicate that he test is valid in predicting the results of the NST and thus appears to be a valid screening tool for fetal well-being and may be a reliable alternative to the NST. Author-abstract.

Davies BL. Niday PA. Nimrod CA. Drake ER. Sprague AE. Trepanier MJ. 1993. "Electronic fetal monitoring: a Canadian survey." Canadian Medical Association Journal 148:1737-42.
OBJECTIVES: To determine the current status of electronic fetal monitoring (EFM) in Canadian teaching and nonteaching hospitals, to review the medical and nursing standards of practice for EFM and to determine the availability of EFM educational programs. DESIGN: National survey in 1989. PARTICIPANTS: The directors of nursing at the 737 hospitals providing obstetric care were sent a questionnaire and asked to have it completed by the most appropriate staff member. The response rate was 80.5% (593/737); 44 hospitals did not have deliveries in 1988 and were excluded. The remaining hospitals varied in size from 8 to 1800 (mean 162.1) beds and had 1 to 7500 (mean 617.1) births in 1988; 18.8% were teaching hospitals. RESULTS: Of the 549 hospitals 419 (76.3%) reported having at least 1 monitor (range 1 to 30; mean 2.6); the mean number of monitors per hospital was higher in the teaching hospitals than in the nonteaching hospitals (6.2 v. 1.7). Manitoba had the lowest mean number of monitors per hospital (1.1) and Ontario the highest (3.7). In 71.8% of the hospitals with monitors almost all of the obstetric patients were monitored at some point during labour. However, 21.6% of the hospitals with monitors had no policy on EFM practice. The availability of EFM educational programs for physicians and nurses varied according to hospital size, type and region. CONCLUSIONS: Most Canadian hospitals providing obstetric services have electronic fetal monitors and use them frequently. Although substantial research has questioned the benefits of EFM, further definitive research is required. In the meantime, a national committee should be established to develop multidisciplinary guidelines for intrapartum fetal assessment.

Donker DK. van Geijn HP. Hasman A. 1993. "Interobserver variation in the assessment of fetal heart rate recordings." European Journal of Obstetrics, Gynecology, & Reproductive Biology 52:21-8.
Electronic fetal heart rate monitoring (EFM) has not fulfilled its expectations. To improve its validity various attempts were made to standardize terminology and assessment of fetal heart rate (FHR) recordings. In a multinational study, 21 experienced obstetricians were asked to segment and classify FHR patterns, recorded in 13 obstetric cases. In addition, the referees were asked to give their interpretation of the FHR pattern, to assess the fetal condition and to propose obstetric management. The kappa statistic showed fair agreement among the obstetricians for the classification of accelerations, baseline segments and decelerations. Poor agreement was found when the referees had to classify baseline variability or the type of deceleration. Also, the clinical assessment of fetal condition and proposals for obstetric management showed poor agreement among the referees. We conclude there is still a lack of unequivocal terminology and definitions in the assessment of FHR recordings.

Ellison, P. H. et al. 1991. "Electronic fetal heart monitoring, auscultation, and neonatal outcome." American Journal of Obst Gyn 164:1281-9.
In a large randomized, controlled study of fetal heart rate monitoring with either continuous electronic fetal heart monitoring or auscultation at specified intervals, only one pattern of deviation in the fetal heart rate correlated significantly with neonatal neurologic examinations at 0 to 48 hours and 72 hours to 1 week: late decelerations in stage 1 and in stage 2. Other variables from labor and delivery, specifically, duration of labor after hospital admission, failure of labor to progress, number of fetal scalp pH values, and presence of meconium were important predictors of neonatal outcome in the regression analyses. The fetal heart rate deviations did contribute significantly to the percent variance accounted for in the regression analyses with neonatal outcomes of Apgar scores at 1 and 5 minutes and serial neonatal neurologic examinations. Author-abstract.

Kaiser, G. 1991. "Do electronic fetal heart rate monitors improve delivery outcomes?" Journal of Fla Med Assoc 78:303-7.
Since the development of electronic fetal heart rate monitors, there has been considerable debate over observable benefits of their use. Early uncontrolled observational studies and retrospective case studies suggested that fetal distress detected by monitoring could help lower both intrapartum and neonatal death rates, serving a utility among high risk deliveries. However, these studies were conducted at a time when neonatal intensive care units and advancing echnologies were also beginning to markedly influence perinatal mortality. Randomized clinical trials of the past 10 years have compared electronic monitoring to routine periodic auscultation and have consistently failed to demonstrate a statistically significant difference in either the perinatal mortality rate or the outcome of high risk pregnancies. A few of these studies, however, did report a lower incidence of neurological complications within the monitored deliveries. The latest research, though, has failed to substantiate any long-term neurological benefits from electronic monitoring. Author-abstract.

Killien, M. G. and K. Shy. 1916. "A randomized trial of electronic fetal monitoring in preterm labor: mothers' views." Birth 1:7-12.
To determine if perceptions of preterm labor and birth differed between women who were monitored by electronic fetal monitoring (EFM) or by periodic auscultation, 135 subjects were randomly assigned to one of two treatment groups on admission to a tertiary perinatal care setting. The first group received external monitoring by continuous Doppler and tocodynamometer when membranes were intact, and with an internal fetal scalp electrode and pressure catheter once membranes were ruptured. The second group received periodic monitoring with a DeLee fetoscope or amplified Doppler. All women were cared for on a one-to-one basis by expert study nurses. Subjects completed a questionnaire about their labor experience during their postpartum hospital stay. There was no statistically significant difference between the two groups on the study measures [T2(7,81) = 13.65; F = 1.82; P greater than 0.05]. Forty-four percent of the variance in women's global evaluation of labor was explained by their perceptions of nursing support. These findings suggest that mothers' perceptions of their preterm labor are less influenced by the technologic interventions used than by the supportive care received from nurses. Author-abstract.

Larson, E. B. et al. 1989. "Fetal monitoring and predictions by clinicians: observations during a randomized clinical trial in very low birth weight infants." Obst Gyn 74:584-9.
Predictions about perinatal outcome in very low birth weight infants were studied in a randomized clinical trial of electronic fetal monitoring and periodic auscultation to assess the effect of diagnostic monitoring information on clinicians' ability to predict perinatal outcomes. The only predictions consistently correct before monitoring information was available were those regarding infant survival (88% correct, kappa [kappa] = 0.40, P less than .001 for the electronic fetal monitoring group; 80% correct, kappa = 0.35, P less han .01 for the periodic auscultation group). After monitoring, predictions of 5-minute Apgar scores and arterial cord pH were significantly more accurate, and clinicians' confidence in their predictions increased significantly in both the electronic fetal monitoring and the auscultation groups. Predictions of 5-minute Apgar scores were significantly more accurate in the electronic fetal monitoring group (92% correct, kappa = 0.80) than in the periodic auscultation group (61% correct, kappa = 0.28) (Z difference = 3.04; P less than .01). We conclude that clinicians gain information during intrapartum monitoring that generally leads to improved predictions and increased confidence in predictions. In this study, hey made more accurate predictions about 5-minute Apgar scores with electronic fetal monitoring, suggesting that electronic fetal monitoring may provide better information about neonatal well-being han does periodic auscultation. Improved information, as measured by clinical predictions, is probably highly valued by patients and clinicians and may be an important determinant of acceptance of this diagnostic technology. Author-abstract.

Morrison, J. C. et al. 1993. "Intrapartum fetal heart rate assessment: monitoring by auscultation or electronic means." American Journal of Obst Gyn 168:63-6.
OBJECTIVE: Our purpose was to assess the frequency with which auscultation could be used as the primary mode of fetal assessment during labor in a busy labor and delivery suite by means of published criteria. STUDY DESIGN: During a 3-month period, 862 patients in labor with live fetuses between 24 and 43 weeks of gestation were available for auscultation in the prospective study. Auscultation was initiated during a contraction and extended for 30 seconds after uterine activity ceased. It was repeated every 15 minutes in the first stage and every 5 minutes in the second stage of labor. RESULTS: In 420 patients this modality was not begun because of inability of the nurses to meet 1:1 staffing requirements. In 19 patients auscultation was not performed because of obesity (12) or patient refusal (7). Of the 423 assessed by auscultation 392 were unable to complete monitoring caused by the frequency requirement (n = 212) or the recording criteria (n = 163). Of the 31 patients where auscultation was successfully completed, there was a 1:1 nurse ratio during the entire labor. CONCLUSIONS: Auscultation with stringent evaluation and recording frequency is not feasible under normal labor and delivery room conditions unless 1:1 nursing care is always available. Author-abstract.

Prentice, A. and T. Lind. 1987. "Fetal heart rate monitoring during labour--too frequent intervention, too little benefit?" Lancet 8572:1375-7.
For many obstetricians and midwives continuous electronic fetal heart rate monitoring during labour has replaced the traditional method of intermittent auscultation. Of the eight prospective randomised controlled trials designed to assess its value in obstetric care, four were concerned with mothers defined as being at high-risk, three with normal or low-risk patients, and the eighth with the total population of a maternity hospital over several months. None suggested any major advantage of continuous fetal heart rate monitoring over intermittent surveillance in terms of neonatal mortality, morbidity, cord blood pH values, or the five minute Apgar score. The rates of caesarean section and forceps delivery were higher in the continuously monitored group. For low-risk mothers here is a good case for a return to the traditional method of intermittent auscultation with its lower false-positive rate, lesser incidence of intervention, and opportunity for greater contact between the maternity care staff and the mother. Author-abstract. 15 Refs.

Ruderman, J. et al. 1993. "Are physicians changing the way they practise obstetrics?" Canadian Medical Association Journal 148:409-15.
OBJECTIVE: To examine trends in obstetric interventions in women at low risk over approximately 3 years. It was postulated that there would be a general reduction in most intervention rates. DESIGN: Retrospective review of hospital records. SETTING: Three downtown hospitals of the University of Toronto, in which academic and nonacademic family physicians and obstetricians practised. PATIENTS: A total of 2365 women in phase 1 (April 1985 to March 1986) and 1277 in phase 2 (May to September 1988) met the inclusion criteria for grade A (pregnancy at no predictable risk) of the Ontario Antenatal Record at the time of admission to hospital. OUTCOME MEASURES: Rates of artificial rupture of the membranes, induction, augmentation, epidural anesthesia, continuous electronic fetal monitoring (EFM), instrumental delivery, episiotomy and cesarean section. RESULTS: The family physicians and the obstetricians had significant decreases (p <0.01) over time in the rates of episiotomy, especially mediolateral, and low forceps delivery. The rate of epidural anesthesia decreased significantly in the obstetrician group. The rates of artificial rupture of the membranes, induction and continuous EFM increased in the two physician groups; the increased rate of EFM was significant in the obstetrician group (p < 0.01). There was no significant change in the rates of augmentation, midforceps delivery, vacuum extraction or cesarean section. All of the trends were found to hold when the intervention rates were analysed according to the women's parity. CONCLUSIONS: Some of the findings reflect recommendations and trends reported in the literature, whereas others are not supported by clear medical evidence. The unpredictable nature of the trends suggests that further study is warranted of the reasons for obstetric trends and for the changes in physicians' practice patterns.

Sandmire, H. F. 1990. "Whither electronic fetal monitoring?" Obst Gyn 76:1130-4.
Largely based on promising animal studies, continuous electronic fetal monitoring (EFM) was introduced into clinical practice in the early 1970s. After almost 20 years of experience, it is now apparent hat the anticipated benefits of this technology have not materialized. Undesirable side effects of EFM include inappropriate operative intervention for some patients and increased liability for physicians and hospitals, resulting in an increase in the costs of obstetric services. After reviewing several research studies, The American College of Obstetricians and Gynecologists concluded that EFM and intermittent auscultation are equivalent methods for intrapartum assessment. We have developed a protocol for the performance of intermittent auscultation, including indicated responses to different levels of bradycardia. This protocol has allowed us to substitute auscultation for EFM in a high percentage of patients using existing nursing personnel. Laboring patients should, at a minimum, receive information on both intermittent auscultation and EFM to enable them to make an informed choice of method for intrapartum fetal assessment. Author-abstract. 30 Refs.

Shy, K. K. et al. 1990. "Effects of electronic fetal-heart-rate monitoring, as compared with periodic auscultation, on the neurologic development of premature infants [see comments]." New England Journal of Medicine 322:588-93.
In a multicenter, randomized clinical trial, we assessed the early neurologic development of 93 children born prematurely whose heart rates were monitored electronically during delivery and compared it with that of 96 children born prematurely whose heart rates were periodically monitored by auscultation. All the children were singletons with cephalic presentation, and all weighed less than or equal to 1750 g at birth. The mental and psychomotor indexes of the Bayley Scales of Infant Development (standardized mean score +/- SD, 100 +/- 16) and a formal neurologic examination were administered at hree follow-up visits (at 4, 8, and 18 months of age, corrected for gestational age). At 18 months, the mean mental-development scores in the groups receiving electronic fetal monitoring and periodic auscultation were 100.5 +/- 2.4 and 104.9 +/- 1.8, respectively (P greater than 0.1). The mean psychomotor-development scores in the wo groups at 18 months were 94.0 +/- 2.4 and 98.3 +/- 1.8, respectively (P greater than 0.1). The incidence of cerebral palsy was higher in the electronically monitored group--20 percent as compared with 8 percent in the group that was monitored by auscultation (P less than 0.03). In the electronic-fetal-monitoring group (but not in the periodic-auscultation group), the risk of cerebral palsy increased with the duration of abnormal fetal-heart-rate patterns, as assessed by retrospective review (chi 2 trend = 12.71, P less than 0.001). The median time to delivery after the diagnosis of abnormal fetal-heart-rate patterns was 104 minutes with electronic fetal monitoring, as compared with 60 minutes with periodic auscultation. We conclude that as compared with a structured program of periodic auscultation, electronic fetal monitoring does not result in improved neurologic development in children born prematurely. Author-abstract.

Strong, T. H. and D. L. Jarles. 1993. "Intrapartum auscultation of the fetal heart rate." American Journal of Obstet Gynecol 168:935-6.
A fetal heart rate recording containing a variable deceleration was played for 120 physicians and nurses. Although mean estimates for baseline and nadir of the fetal heart rate and duration of the deceleration were not significantly different from the actual values, individual estimates of the three parameters were widely distributed. Adjunctive techniques for intrapartum fetal heart rate auscultation are recommended. Author-abstract.

Vintzileos, A. M. et al. 1993. "A randomized trial of intrapartum electronic fetal heart rate monitoring versus intermittent auscultation." Obstetrics & Gynecology 81:899-907.
OBJECTIVE: To determine whether continuous intrapartum electronic fetal heart rate monitoring (EFM) is associated with decreased perinatal mortality and morbidity compared with intermittent auscultation. METHODS: The study was conducted simultaneously at two university hospitals in Athens, Greece (Alexandra and Marika Iliadi Hospitals) from October 1, 1990 to June 30, 1991. All patients with singleton living fetuses and gestational ages of 26 weeks or greater were eligible for inclusion. The participants were assigned to continuous EFM or intermittent auscultation based on the flip of a coin. Both groups were followed during labor according to the most recent ACOG guidelines. However, fetal scalp blood pH and crossover from one group to the other were not used. RESULTS: A total of 1428 patients were included, 746 in the EFM group and 682 in the auscultation group. There were no differences between the groups in erms of maternal age, gravidity, parity, gestational age, and number of antepartum high-risk factors. More patients monitored electronically received oxytocin for either augmentation (52.4 versus 38.1%; P = .0001) or induction (15.6 versus 7%; P = .0001). The length of labor was longer in the EFM group (first stage 6.1 +/- 4.3 versus 5.5 +/- 3.7 hours; P = .006; second stage 29.4 +/- 18.6 versus 26.9 +/- 16.9 minutes; P = .01). There was a higher incidence of nonreassuring fetal heart rate patterns in the EFM group (23.4 versus 10.7%; P = .0001) and a higher rate of surgical intervention (11.2 versus 4.8%; P = .0001). This difference pertained to both vacuum extraction (5.8 versus 2.4%; P = .002) and cesarean delivery for suspected fetal distress (5.3 versus 2.3%; P = .005). There were no differences in 1- and 5-minute Apgar scores, fetal acidosis at birth, need for neonatal resuscitation, neonatal intensive care unit admission, use of assisted ventilation, neonatal hospital stay, or any other neonatal complications. Two neonatal deaths occurred in he EFM group and nine perinatal deaths in the auscultation group (two intrapartum and seven neonatal deaths). The perinatal mortality rates were 2.6 per 1000 and 13 per 1000 total births, respectively (P = .04). The two deaths in the EFM group and three of the neonatal deaths in the auscultation group may not have been prevented by intrapartum monitoring; however, four neonatal deaths from the auscultation group occurred in depressed (5-minute Apgar scores less han 7), acidotic (cord artery pH at or below 7.13) infants. The perinatal death rate related to fetal hypoxia was significantly less in the EFM group (zero of 746 versus six of 682; P = .03). CONCLUSION: In this controlled trial, intrapartum EFM, as the primary and only method of intrapartum fetal surveillance, was associated with decreased perinatal mortality due to fetal hypoxia but also with higher rates of surgical intervention for suspected fetal distress. Author-abstract.

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