OBJECTIVE: Our purpose was to compare continuous intrapartum electronic fetal heart rate monitoring with intermittent auscultation for detecting fetal acidemia at birth.
STUDY DESIGN: Data from a previously published randomized trial of electronic fetal heart rate monitoring versus intermittent auscultation were analyzed to identify any differences between the two methods in detecting fetal acidemia at birth. Fetal acidemia at birth was defined as the presence of cord blood arterial pH < 7.15.
RESULTS: A total of 1419 patients with umbilical cord blood acid-base measurements were identified, 739 in the electronic FHR monitoring group and 680 in the auscultation group. Electronic FHR monitoring had significantly better sensitivity (97% vs 34%, p < 0.001), lower specificity (84% vs 91%, p < 0.001), higher positive predictive value (37% vs 22%, p < 0.05), and higher negative predictive value (99.5% vs 95%, p < 0.001) in detecting fetal acidemia at birth. In addition, electronic FHR monitoring was significantly better in detecting all types of acidemia: metabolic (95.5% vs 26.5%, p < 0.001), mixed (95% vs 37.5%, p < 0.001), and respiratory (100% vs 41.5%, p < 0.001).
CONCLUSION: These data suggest that electronic FHR monitoring is superior to intermittent auscultation in detecting fetal acidemia at birth.
OBJECTIVE: To compare the efficacy in detecting signs of fetal hypoxia in labour of intermittent (I-group) versus continuous (C-group) electronic fetal monitoring in women with low or moderate risk factors for fetal distress.
DESIGN: A prospective, randomised study.
SETTING: A tertiary referral centre.
SUBJECTS: Four thousand and forty-four parturients at low risk for obstetric complications with a reactive fetal heart rate admission test at arrival in labour. During the study period (October 5 1989 to May 31 1991), 5647 women were delivered in the labour ward. Of these, 1178 women (20.9%) were excluded because of high risk factors in pregnancy or at admission for labour, including women undergoing elective caesarean section. Of the remaining 4469 women 4044 (90.5%) were randomised to either intermittent (n = 2015) or continuous monitoring (n = 2029) during the first stage of labour.
METHODS: In the C-group the fetal heart rate was recorded continuously with electronic fetal monitoring during the first stage of labour. In the I-group the fetal heart rate was recorded with electronic fetal monitoring for 10 to 30 min every 2 to 2.5 h during the first stage of labour, and the fetal heart rate was auscultated every 15 to 30 min in between recording periods. If complications occurred, recording was changed to continuous. In the second stage of labour all the women were monitored continuously. Umbilical cord artery acid-base status was assessed at birth.
MAIN OUTCOME MEASURES: Duration of electronic fetal monitoring, rates of abnormal fetal heart rate patterns, caesarean section for fetal distress, acidosis in umbilical cord arterial blood at birth, Apgar scores of less than 7 at 1 or 5 min, and referrals to the neonatal intensive care unit.
RESULTS: There were no significant differences between the study groups in the incidence of ominous fetal heart rate recordings: 6.3% (I-group) versus 6.6% (C-group), or the interval from arrival to first detected abnormal fetal heart rate, although the number of suspicious fetal heart rate patterns was higher in the C-group (28.6%) than in the I-group (24.6%). In the I-group electronic fetal monitoring was performed for (median monitoring time) 38.8% of the first stage of labour as compared with 78.6% in the C-group. The incidence of caesarean section for fetal distress was similarly low in both groups: 1.2% versus 1.0%. There were no significant differences in the immediate neonatal outcome in terms of umbilical artery pH, Apgar scores, or admissions to the neonatal care unit.
CONCLUSIONS: Intermittent use of electronic fetal monitoring at regular intervals (with stethoscopic auscultation in between) appears to be as safe as continuous electronic fetal monitoring in low risk labours.
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 terms 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 the 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 than 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.
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.
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 three 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 two 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.
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.
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 than .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, they 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 than 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.
Intrapartum electronic fetal heart rate (FHR) monitoring and fetal blood gas sampling were compared with periodic auscultation of FHR in a multicentered randomized trial of preterm singleton pregnancies with fetal weights of 700-1750 g. Two hundred forty-six pregnancies were studied (electronic FHR monitoring N = 122, auscultation N = 124). Perinatal or infant death was associated with 14% of pregnancies with electronic FHR monitoring and 15% with auscultation. No significant differences were noted in the prevalence of low five-minute Apgar scores, intrapartum acidosis, intracranial hemorrhage, or frequency of cesarean section (P greater than .10). Compared with electronic FHR monitoring, intrapartum auscultation as done in this study is unlikely to be associated with detectable differences in perinatal outcomes within the high-risk setting of preterm labor.
In a prospective clinical randomized investigation 487 women had the condition of the fetus during labour supervised by means of stethoscope (AUS), while 482 women went through labour under surveillance of electronic fetal monitoring, cardiotocography (EFM). 349 women refused to participate in the investigation (NAI) and had delivery conducted according to the normal procedures of the department (70% AUS, 30% EFM). Significantly more pathological fetal heart rate patterns (FHR) were found in the EFM group compared to the AUS group in both the first and the second stage of labour. As a result significantly more vacuum extractions were performed in the EFM group than in the AUS group, while no statistical difference was found between the groups in the incidence of acute cesarean sections carried out for asphyxia. One case of intrapartum death occurred in the AUS group. No differences were found in Apgar scores after 1 and 5 min or in neonatal morbidity at examination on the 2nd and 5th days after delivery. A tendency towards more biochemically compromised children was found in the AUS group. The specificity for both methods was found to be acceptably high (80%), while the predictive value for both methods was low (50%). More research is therefore urgently needed to evaluate supplementary investigations and parameters for the evaluation of the intrapartum fetal condition.
