Monitoring a baby's heart rate during labour with and without a computerised decision aid: a comparison of pregnancy outcomes

When a woman goes into labour, maternity care providers may choose to monitor the baby's heart rate during the birth to ensure the baby is healthy. An abnormal heart rate is a strong indicator that the baby is stressed, for example because the baby has insufficient oxygen. If there is a problem with the baby's heart rate, care providers may wish to perform additional tests or speed up delivery to avoid major complications. A cardiotocography (CTG) machine is frequently used to monitor the heart rate, which is measured in relation to the woman's contractions during labour. The machine prints the results on a strip known as a CTG trace or they are viewed directly on a visual display unit. In some cases, however, it is difficult for maternity care providers to determine whether the CTG trace is normal or abnormal, and this can result in unnecessary intervention or a delay in providing necessary interventions. Computerised decision aids, also referred to as expert systems (ESs), have a computerised knowledge base that can be matched and may be able to guide CTG interpretation to avoid such situations.

This review aimed to examine birth-related outcomes among women who were monitored using continuous or intermittent CTG during labour with an ES with continuous or intermittent CTG monitoring without an ES. We did not identify any studies comparing CTG monitoring during labour with an ES versus intermittent auscultation.

However, we did identify two randomised controlled trials looking at birth-related outcomes among women who were monitored using a CTG with an ES compared to women who were monitored using CTG without an ES. Although the review identified two eligible randomised controlled trials that were at a low risk of bias, only one trial (involving 220 women) examined the outcomes of interest in this review. Data relating to death of the baby within the first 28 days of life (early neonatal death) was unavailable but the study reported that none of the babies died before being born (fetal deaths).

There was no strong evidence that CTG with an ES reduces the likelihood of caesarean delivery, forceps-assisted vaginal birth or adverse baby outcomes (such as fetal acidaemia, neonatal seizures, brain injury due to lack of oxygen (hypoxic ischaemic encephalopathy), Apgar score less than seven at five minutes or admission to the neonatal intensive care unit).

These results should be interpreted with caution since the trial was underpowered as too few women were included in the trial to detect modest differences in adverse outcomes. Larger randomised controlled trials are necessary to see if CTG with an ES reduces adverse outcomes for women and their babies during the birth.

Authors' conclusions: 

Two trials met the inclusion criteria for this review but one trial did not provide data for any of this review's outcomes. The single trial that did contribute data was underpowered to evaluate the association between CTG monitoring with an ES and the primary outcomes of interest. No recommendations for clinical practice can be made at this time. Adequately powered trials are necessary before the impact of ESs for fetal assessment in labour can be determined.

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Background: 

Cardiotocography (CTG) records the fetal heart rate in relation to maternal uterine contractions and is one of the most common forms of fetal assessment during labour. Despite guidelines for CTG interpretation, substantial inter- and intra-observer variation in interpretation has been reported among maternity care providers. Misinterpretation of CTG readings can lead to poor decisions, which can result in unnecessary intervention or delay or withholding of necessary intervention. Expert systems (ESs) represent a type of applied artificial intelligence, which can assist in complex clinical decision-making and potentially serve as a mechanism to improve interpretation of fetal heart rate tracings.

Objectives: 

To evaluate the effectiveness of continuous or intermittent CTG monitoring during labour with an ES compared with (1) continuous or intermittent CTG monitoring during labour without an ES or (2) intermittent auscultation with a Pinard stethoscope or hand-held Doppler ultrasound device. Outcomes of interest included incidence of perinatal mortality, caesarean delivery, operative vaginal birth, fetal blood sampling, artificial rupture of amniotic membranes, oxytocin augmentation of labour, maternal satisfaction with labour, neonatal seizures, fetal acidaemia, hypoxic ischaemic encephalopathy, admission to neonatal special care and/or neonatal intensive care unit and an Apgar score less than seven at five minutes.

Search strategy: 

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (27 October 2014), Open Grey (6 October 2014) ProQuest Dissertation & Theses Database (6 October 2014) and reference lists of retrieved studies.

Selection criteria: 

Randomised and quasi-randomised controlled trials comparing continuous or intermittent CTG monitoring during labour with an ES with continuous or intermittent CTG monitoring without an ES were eligible for this review. Trials comparing continuous or intermittent CTG monitoring during labour with an ES with intermittent auscultation with a Pinard or hand-held Doppler were also eligible.

Data collection and analysis: 

Two review authors independently assessed the eligibility and quality of the trials as well as extracted data to ensure accuracy. The authors of included trials were contacted to clarify aspects of the study design that were not clearly reported in the original trial publications.

Main results: 

No studies comparing CTG monitoring during labour with an ES to intermittent auscultation were identified.

Two randomised controlled trials comparing CTG monitoring during labour with an ES versus CTG without an ES were identified and included in the qualitative synthesis of results, but only one trial (n = 220) provided data for quantitative analysis. Both trials were classified as low risk of bias.

There was no strong evidence that CTG with an ES has an effect on the incidence of caesarean delivery (risk ratio (RR) 0.61; 95% confidence interval (CI) 0.35 to 1.04) when compared with CTG with fetal blood sampling.There was no strong evidence supporting a reduction in the incidence of neonatal seizures (RR 0.33; 95% CI 0.01 to 8.09) or fetal acidaemia (RR 0.50; 95% CI 0.09 to 2.67) in women monitored using a CTG with an ES versus a CTG without an ES. Overall perinatal mortality could not be ascertained for this trial since data on early neonatal deaths were unavailable. Although fetal deaths were recorded, no fetal deaths occurred in either arm of the trial, and thus no risk estimates could be derived.

There was no strong evidence supporting a reduction in the incidence of forceps-assisted vaginal birth (RR 0.50; 95% CI 0.05 to 5.43), hypoxic ischaemic encephalopathy (RR 0.33; 95% CI 0.01 to 8.09), admission to the neonatal intensive care unit (RR 0.40; 95% CI 0.08 to 2.02) or an Apgar less than seven at five minutes (RR 0.50; 95% CI 0.13 to 1.95).

The trial did not report on artificial rupture of amniotic membranes, oxytocin augmentation of labour or maternal satisfaction with labour.

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