ST analysis of the fetal electrocardiogram during labor: Nordic observational multicenter study

Amer‐Wåhlin, Isis; Børdahl, Per E.; Eikeland, Torunn; Hellsten, Charlotte; Norén, Håkan; Sørnes, Torgrim; Rosén, Karl G.

doi:10.1080/jmf.12.4.260.266

Cited by 52 publications

(26 citation statements)

References 18 publications

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“…The current database has been analysed in another study regarding ST waveform changes in fetal ECG. 9 All the acidotic fetuses displayed an increase in T/QRS ratio, with ST segment elevation on average 24 (median), 18 -33 minutes (95th CI) before the end of recording. In the present study, the median time lag between the end of recording and delivery was 4 minutes, 1 -9 minutes (95th CI) in acidotic fetuses, of whom all but one were delivered vaginally.…”

Section: Methodsmentioning

confidence: 93%

“…Also, it has been applied as a marker of significant acidosis in previous studies on intrapartum asphyxia. 9,13,14 In the human fetus, acute hypoxia causes a small increase in fetal heart rate, but in severe acidosis fetal heart rate gradually declines, resulting in bradycardia. 15,16 The reduction in fetal heart rate variability in the presence of bradycardia appears to be a rather late sign of severe acidosis, 5,17 and is associated with reduced cerebral oxygen consumption and poor fetal outcome.…”

Section: Discussionmentioning

confidence: 99%

“…The recordings were collected from 12 Nordic delivery units from June 1998 to January 1999 as a part of a Nordic observational multicentre study. 9 Those eligible for the study were women in active labour at more than 35 completed gestational weeks, and for whom a clinical decision had been made to apply a fetal scalp electrode for continuous internal cardiotocography recording. The umbilical cord arterial acid -base status was analysed after delivery.…”

Section: Methodsmentioning

confidence: 99%

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Marked fetal acidosis and specific changes in power spectrum analysis of fetal heart rate variability recorded during the last hour of labour

Siira

Ojala

Vahlberg

et al. 2005

BJOG

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Objective To assess whether intrapartum acidosis affects specific components of fetal heart rate variability.Design Prospective clinical study.Setting Twelve Nordic delivery units.Subjects Fetal heart rate variability was studied in 334 fetuses divided into two groups according to cord pH value: the acidotic group (cord arterial pH <7.05 at birth, n ¼ 15) and the control group (cord arterial pH !7.05 at birth, n ¼ 319). Methods In spectral analysis of fetal heart rate variability, frequencies were integrated over the total frequency band (0.04 -1.0 Hz), low-frequency band (0.04 -0.15 Hz) and high-frequency band (0.15 -1.0 Hz). We also calculated the low-to-high frequency ratio. Main outcome measures The spectral bands of fetal heart rate variability were compared between the acidotic and control fetuses. Results We found that during the last hour of monitoring, baseline fetal heart rate gradually decreased, whereas total, low-frequency and high-frequency fetal heart rate variability initially increased but then, near the delivery, decreased in the acidotic fetuses when compared with the controls. Low-to-high frequency ratio was greater in the acidotic group during the whole study period (P ¼ 0.002). Cord artery pH was inversely associated with total fetal heart rate variability (P < 0.001), low-frequency fetal heart rate variability (P < 0.001) and low-to-high frequency ratio (P ¼ 0.004). Conclusions Marked fetal acidosis was associated with frequency-specific changes in fetal heart rate variability as reflecting the compensation ability of autonomic nervous activation during the last hour of labour.

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Section: Methodsmentioning

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Marked fetal acidosis and specific changes in power spectrum analysis of fetal heart rate variability recorded during the last hour of labour

Siira

Ojala

Vahlberg

et al. 2005

BJOG

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“…[2] Encouraging data demonstrate that intrapartum fetal ECG analysis can reduce newborn acidemia, hypoxic ischemic encephalopathy, [3] and cesarean deliveries. [4] However, the only clinically-available device for fetal ECG analysis – the STAN monitor from Neoventa -- requires an invasive fetal scalp electrode, limiting its use to a subset of pregnant women who are laboring with ruptured membranes and a dilated cervix.…”

Section: Introductionmentioning

confidence: 99%

Clinically accurate fetal ECG parameters acquired from maternal abdominal sensors

Clifford

Sameni

Ward³

et al. 2011

American Journal of Obstetrics and Gynecology

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OBJECTIVE To evaluate the accuracy of a novel system for measuring fetal heart rate and ST-segment changes using non-invasive electrodes on the maternal abdomen. STUDY DESIGN Fetal ECGs were recorded using abdominal sensors from 32 term laboring women who had a fetal scalp electrode (FSE) placed for a clinical indication. RESULTS Good quality data for FHR estimation was available in 91.2% of the FSE segments, and 89.9% of the abdominal electrode segments. The root mean square (RMS) error between the FHR data calculated by both methods over all processed segments was 0.36 beats per minute. ST deviation from the isoelectric point ranged from 0 to 14.2% of R-wave amplitude. The RMS error between the ST change calculated by both methods averaged over all processed segments was 3.2%. CONCLUSION FHR and ST change acquired from the maternal abdomen is highly accurate and on average is clinically indistinguishable from FHR and ST change calculated using FSE data.

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“…The addition of fetal electrocardiogram ST waveform analysis to conventional CTG (STAN ® , Neoventa, Gothenburg, Sweden) has been shown to increase the identification of fetuses with metabolic acidosis [9]. A systematic review of the first three trials comparing CTG+ST monitoring with conventional CTG showed that the former significantly decreases the rates of fetal blood sampling, neonatal encephalopathy and operative delivery, and is associated with a borderline reduction in the incidence of umbilical artery metabolic acidosis [10].…”

Section: Introductionmentioning

confidence: 99%

A randomised clinical trial of intrapartum fetal monitoring with computer analysis and alerts versus previously available monitoring

Ayres‐de‐Campos¹,

Ugwumadu

Banfield

et al. 2010

BMC Pregnancy Childbirth

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BackgroundIntrapartum fetal hypoxia remains an important cause of death and permanent handicap and in a significant proportion of cases there is evidence of suboptimal care related to fetal surveillance. Cardiotocographic (CTG) monitoring remains the basis of intrapartum surveillance, but its interpretation by healthcare professionals lacks reproducibility and the technology has not been shown to improve clinically important outcomes. The addition of fetal electrocardiogram analysis has increased the potential to avoid adverse outcomes, but CTG interpretation remains its main weakness. A program for computerised analysis of intrapartum fetal signals, incorporating real-time alerts for healthcare professionals, has recently been developed. There is a need to determine whether this technology can result in better perinatal outcomes.Methods/designThis is a multicentre randomised clinical trial. Inclusion criteria are: women aged ≥ 16 years, able to provide written informed consent, singleton pregnancies ≥ 36 weeks, cephalic presentation, no known major fetal malformations, in labour but excluding active second stage, planned for continuous CTG monitoring, and no known contra-indication for vaginal delivery. Eligible women will be randomised using a computer-generated randomisation sequence to one of the two arms: continuous computer analysis of fetal monitoring signals with real-time alerts (intervention arm) or continuous CTG monitoring as previously performed (control arm). Electrocardiographic monitoring and fetal scalp blood sampling will be available in both arms. The primary outcome measure is the incidence of fetal metabolic acidosis (umbilical artery pH < 7.05, BDecf > 12 mmol/L). Secondary outcome measures are: caesarean section and instrumental vaginal delivery rates, use of fetal blood sampling, 5-minute Apgar score < 7, neonatal intensive care unit admission, moderate and severe neonatal encephalopathy with a marker of hypoxia, perinatal death, rate of internal monitoring, tracing quality, and signal loss. Analysis will follow an intention to treat principle. Incidences of primary and secondary outcomes will be compared between groups. Assuming a reduction in metabolic acidosis from 2.8% to 1.8%, using a two-sided test with alpha = 0.05, power = 0.80, and 10% loss to follow-up, 8133 women need to be randomised.DiscussionThis study will provide evidence of the impact of intrapartum monitoring with computer analysis and real-time alerts on the incidence of adverse perinatal outcomes, intrapartum interventions and signal quality. (Current controlled trials ISRCTN42314164)

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ST analysis of the fetal electrocardiogram during labor: Nordic observational multicenter study

Abstract: The STAN clinical guidelines identify fetuses at risk of intrapartum asphyxia.

Cited by 52 publications

References 18 publications

Marked fetal acidosis and specific changes in power spectrum analysis of fetal heart rate variability recorded during the last hour of labour

Marked fetal acidosis and specific changes in power spectrum analysis of fetal heart rate variability recorded during the last hour of labour

Clinically accurate fetal ECG parameters acquired from maternal abdominal sensors

A randomised clinical trial of intrapartum fetal monitoring with computer analysis and alerts versus previously available monitoring

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