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Intervention Review

Fetal electrocardiogram (ECG) for fetal monitoring during labour

  1. JP Neilson

Editorial Group: Cochrane Pregnancy and Childbirth Group

Published Online: 22 APR 2003

DOI: 10.1002/14651858.CD000116


How to Cite

Neilson JP. Fetal electrocardiogram (ECG) for fetal monitoring during labour. The Cochrane Database of Systematic Reviews 2003, Issue 2. Art. No.: CD000116. DOI: 10.1002/14651858.CD000116.

Author Information

*Prof James P Neilson, Professor of Obstetrics and Gynaecology/Head of School of Reproductive and Developmental Medicine, Division of Perinatal and Reproductive Medicine, The University of Liverpool, First Floor, Liverpool Women's NHS Foundation Trust, Crown Street, Liverpool, L8 7SS, UK. jneilson@liverpool.ac.uk.

Publication History

  1. Published Online: 22 APR 2003

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This is not the most recent version of the article. View current version (31 MAY 2013)

 

Abstract

  1. Top of page
  2. Abstract
  3. Synopsis

Background

Animal and human studies have shown that fetal hypoxaemia during labour can alter the shape of the fetal electrocardiogram (ECG) waveform, notably (1) the relation of the PR to RR intervals and (2) elevation or depression of the ST segment. Technical systems have therefore been developed to monitor the fetal ECG during labour as an adjunct to continuous electronic fetal heart rate monitoring with the aim of improving fetal outcome and minimising unnecessary obstetric interference.

Objectives

To compare the effects of analysis of fetal ECG waveforms during labour with alternative methods of fetal monitoring.

Search strategy

The Cochrane Pregnancy and Childbirth Group trials register was searched (September 2002).

Selection criteria

Randomised trials comparing fetal ECG waveform analysis with alternative methods of fetal monitoring during labour.

Data collection and analysis

Trial quality assessment and data extraction were performed by the reviewer, without blinding.

Main results

Three trials including a total of 8357 pregnant women were included. The trials were of sound methodological quality. All three trials assessed the use of the fetal ECG as an adjunct to continuous electronic fetal heart rate monitoring during labour. One study assessed PR intervals; two assessed the ST segment. The use of ST waveform analysis (7400 women) was associated with fewer babies with severe metabolic acidosis at birth (cord pH less than 7.05 and base deficit greater than 12 mmol/L) (relative risk (RR) 0.44, 95% confidence interval (CI) 0.26 to 0.75, data from 6672 babies). This was achieved along with fewer fetal scalp samples during labour (RR 0.86, 95% CI 0.76 to 0.98) and fewer operative deliveries (RR 0.89, 95% CI 0.82 to 0.97). Apart from a trend (that did not achieve statistical significance) towards fewer operative deliveries (RR 0.87, 95% CI 0.76 to 1.01), there was little evidence that monitoring by PR interval analysis conveyed any benefit. This may reflect limitations of the technique or, alternatively, the smaller numbers available for analysis from the single trial (957 women).

Authors' conclusions

These findings support the use of fetal ST waveform analysis when a decision has been made to undertake continuous electronic fetal heart rate monitoring during labour. However, in most labours, technically satisfactory cardiotocographic traces can be obtained by external ultrasound monitors which are less invasive than internal scalp electrodes (which are required for electrocardiographic (ECG) analysis). A better approach might be to restrict fetal ST waveform analysis to those fetuses demonstrating disquieting features on cardiotocography.

 

Synopsis

  1. Top of page
  2. Abstract
  3. Synopsis

Plain language summary

Monitoring the baby's heart using ECG plus CTG during labour helps mothers and babies when continuous monitoring is needed

Electronic heart monitoring may be suggested if doctors think the baby is not getting enough oxygen during labour. Two methods may be used. Cardiotocography (CTG) measures the baby's heart rate. Electrocardiography (ECG) measures the heart's electrical activity and the pattern of the heart beats. ECG uses an electrode, passed through the woman's cervix, and attached to the baby's head. The review of trials found that using ECG plus CTG results in fewer blood samples taken from the baby's scalp, less surgical assistance and better oxygen levels at birth than CTG alone.