A critical appraisal of the evidence for using cardiotocography plus ECG ST interval analysis for fetal surveillance in labor. Part I: the randomized controlled trials

Authors

  • 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 a consulting Global Medical Adviser. Jörg Kessler once received a lecture fee from Neoventa Medical AB. Branka M Yli has taught at ST analysis 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 no conflicts of interest to declare.

Abstract

We reappraised the five randomized controlled trials that compared cardiotocography plus ECG ST interval analysis (CTG+ST) vs. cardiotocography. The numbers enrolled ranged from 5681 (Dutch randomized controlled trial) to 799 (French randomized controlled trial). The Swedish randomized controlled trial (= 5049) was the only trial adequately powered to show a difference in metabolic acidosis, and the Plymouth randomized controlled trial (= 2434) was only powered to show a difference in operative delivery for fetal distress. There were considerable differences in study design: the French randomized controlled trial used different inclusion criteria, and the Finnish randomized controlled trial (= 1483) used a different metabolic acidosis definition. In the CTG+ST study arms, the larger Plymouth, Swedish and Dutch trials showed lower operative delivery and metabolic acidosis rates, whereas the smaller Finnish and French trials showed minor differences in operative delivery and higher metabolic acidosis rates. We conclude that the differences in outcomes are likely due to the considerable differences in study design and size. This will enhance heterogeneity effects in any subsequent meta-analysis.

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