Sensitivity and specificity of intrapartum computerised FIGO criteria for cardiotocography and fetal scalp pH during labour: multicentre, observational study

Objective  To identify sensitivity and specificity of computerised cardiotocography (CTG) analysis for fetal acidosis during delivery. Design  Retrospective observational study. Setting  Tertiary referral labour ward, Technical University Munchen (TUM) and University Witten/Herdecke (UWH). Population  All deliveries, which had at least one fetal scalp pH measurement and electronically saved CTG traces, between 2000 and 2002 (TUM) and between 2004 and 2005 (UWH). Method  Correlation analysis of fetal scalp pH values and computerised International Federation of Obstetrics and Gynecology (FIGO) classification using ‘CTG Online®’ program of digitally saved CTG traces. Main outcome measures  Fetal scalp pH values, FIGO parameter (baseline, variability, acceleration and deceleration) using computerised analysis. Results  Both collectives showed a high sensitivity (95.0%) for computerised FIGO classification ‘suspect’ and ‘pathological’, together with a low specificity (21.8%) for fetal acidosis. The most sensitive single FIGO parameter was deceleration. Very low sensitivity (<50%) was shown for the parameters variability and acceleration. Conclusions  Computerised CTG analysis is highly sensitive for fetal acidosis and can be used as an objective adjunctive criterion during delivery. Further CTG data are needed to adjust and optimise each FIGO parameter and increase sensitivity and specificity.