Antenatal cardiotocography for fetal assessment

Abstract

BackgroundCardiotocography (CTG) is a continuous recording of the fetal heart rate obtained via an ultrasound transducer placed on the mother's abdomen. CTG is widely used in pregnancy as a method of assessing fetal well-being, predominantly in pregnancies with increased risk of complications. ObjectivesTo assess the effectiveness of antenatal CTG (both traditional and computerised assessments) in improving outcomes for mothers and babies during and after pregnancy. Search methodsWe searched the Cochrane Pregnancy and Childbirth Group's Trials Register (26 June 2015) and reference lists of retrieved studies. Selection criteriaRandomised and quasi-randomised trials that compared traditional antenatal CTG with no CTG or CTG results concealed; computerised CTG with no CTG or CTG results concealed; and computerised CTG with traditional CTG. Data collection and analysisTwo review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. Main resultsSix studies (involving 2105 women) are included. Overall, the included studies were not of high quality, and only two had both adequate randomisation sequence generation and allocation concealment. All studies that were able to be included enrolled only women at increased risk of complications.Comparison of traditional CTG versus no CTG showed no significant difference identified in perinatal mortality (risk ratio (RR) 2.05, 95% confidence interval (CI) 0.95 to 4.42, 2.3% versus 1.1%, four studies, N = 1627, low quality evidence) or potentially preventable deaths (RR 2.46, 95% CI 0.96 to 6.30, four studies, N = 1627), though the meta-analysis was underpowered to assess this outcome. Similarly, there was no significant difference identified in caesarean sections (RR 1.06, 95% CI 0.88 to 1.28, 19.7% versus 18.5%, 1 Antenatal cardiotocography for fetal assessment (Review)

Commentary on ‘Antenatal cardiotocogram quality and interpretation using computers’

“…The system 8000 is still commercially available from Huntleigh (who acquired Sonicaid in the 1990s) but to date no other manufacturer has adopted a similar approach, and antenatal computerised fetal heart rate analysis has not been widely adopted, because of the difficulty of predicting the cases in which it might be useful. The 2012 Cochrane systematic review of antenatal cardiotocography included only six randomised studies involving 2105 women, and these were mostly of poor quality . The meta‐analysis was therefore underpowered to assess potentially preventable deaths; there were only two studies in which this aspect could be assessed, and the relative risk of 0.23 had 95% confidence intervals from 0.04 to 1.29.…”

Corrigendum

“…The two previous sentences, ‘The meta‐analysis was therefore underpowered to assess potentially preventable deaths; there were only two studies in which this aspect could be assessed, and the relative risk of 0.23 had 95% confidence intervals from 0.04 to 1.29. Although the relative risk is encouraging, the numbers are clearly too small to conclude that antenatal monitoring per se is beneficial’, correctly reflect the findings of the referenced Cochrane review.…”

Commentary on ‘Unstressed antepartum cardiotocography in the management of the fetus suspected of growth retardation’

“…These last two trials had the additional problem that since traditional CTG had not been shown to be effective, even well‐designed trials would have been difficult to interpret. It is hardly surprising that 35 years later the Cochrane review of antenatal CTG still concludes: ‘There is no clear evidence that antenatal CTG improves perinatal outcome’ …”