Computerized cardiotocography and Dawes-Redman criteria: how should we interpret criteria not-met?

Antenatal computerized cardiotocography, often abbreviated to cCTG, provides an objective way of assessing the fetal heart rate (FHR), most commonly analyzed according to the Dawes-Redman criteria. First described four decades ago, various components of the FHR were associated with adverse perinatal outcomes and poor fetal acid-base balance. While various proprietary devices offer analysis based on Dawes-Redman criteria, little evidence-based guidance exists from prospective studies outside of the specific area of hypoxia related to fetal growth restriction. Objective assessment of the CTG is an important step towards reducing variable interpretation. However, the widespread adoption of antenatal cCTG and its categorization of traces as ‘criteria met’ and ‘criteria not met’ has led to genuine uncertainty regarding situations where cCTG criteria for fetal wellbeing are not met. Many women undergoing monitoring in modern obstetric practice are at low-risk of perinatal adverse outcome, hence, the potential for obstetric over-intervention exists where cCTG criteria are not met, without clear evidence of benefit. This opinion piece seeks to establish where there is consensus, and where evidence is lacking in relation to antenatal fetal monitoring using the cCTG and Dawes-Redman criteria.