A critical appraisal of the evidence for using cardiotocography plus ECG ST interval analysis for fetal surveillance in labor. Part II: the meta-analyses


  • Per Olofsson,

    Corresponding author
    1. Department of Obstetrics and Gynecology, Institution of Clinical Sciences, Skåne University Hospital, Lund University, Malmö, Sweden
    • Correspondence

      Per Olofsson, Department of Obstetrics and Gynecology, Skåne University Hospital, S-20502 Malmö, Sweden.

      E-mail: per.olofsson@med.lu.se

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  • Diogo Ayres-de-Campos,

    1. Department of Obstetrics and Gynecology, Medical School – S. Joao Hospital, Institute of Biomedical Engineering, Porto University, Porto, Portugal
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  • Jörg Kessler,

    1. Department of Obstetrics and Gynecology, Haukeland University Hospital, Bergen, Norway
    2. Department of Clinical Sciences, Clinical Fetal Physiology Research Group, Bergen University, Bergen, Norway
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  • Britta Tendal,

    1. Danish Health and Medicines Authority, Copenhagen, Denmark
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  • Branka M. Yli,

    1. Delivery Department, Mother and Child Clinic, Oslo University Hospital, Oslo, Norway
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  • Lawrence Devoe

    1. Department of Obstetrics and Gynecology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, USA
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  • Per Olofsson was co-author of the Swedish RCT and has cooperated with FBS equipment sales companies in Sweden and Denmark (Medexa Medicinsk Service AB, LiNA Medical A/S) and with the STAN manufacturer Neoventa Medical AB, where he is currently consulting Global Medical Adviser. Jörg Kessler has received a lecture fee once from Neoventa Medical AB. Branka M. Yli has taught STAN courses arranged by SCAN-MED A/S, Norway. Lawrence Devoe is a paid US Medical Adviser to Neoventa Medical AB. Diogo Ayres-de-Campos and Britta Tendal have stated explicitly that they have no conflicts of interest in connection with this article.


We appraised the methodology, execution and quality of the five published meta-analyses that are based on the five randomized controlled trials which compared cardiotocography (CTG)+ST analysis to cardiotocography. The meta-analyses contained errors, either created de novo in handling of original data or from a failure to recognize essential differences among the randomized controlled trials, particularly in their inclusion criteria and outcome parameters. No meta-analysis contained complete and relevant data from all five randomized controlled trials. We believe that one randomized controlled trial excluded in two of the meta-analyses should have been included, whereas one randomized controlled trial that was included in all meta-analyses, should have been excluded. After correction of the uncovered errors and exclusion of the randomized controlled trial that we deemed inappropriate, our new meta-analysis showed that CTG+ST monitoring significantly reduces the fetal scalp blood sampling usage (risk ratio 0.64; 95% confidence interval 0.47–0.88), total operative delivery rate (0.93; 0.88–0.99) and metabolic acidosis rate (0.61; 0.41–0.91).