A validation of electrohysterography for uterine activity monitoring during labour.

OBJECTIVES: Validation of electrohysterography (EHG) as a method for uterine activity monitoring during labour by comparing with intra-uterine pressure catheter (IUPC) recordings. DESIGN: Prospective observational study. SETTING: Labour ward in a tertiary centre in the Netherlands. POPULATION: Thirty-two women in labour. METHODS: Simultaneous recording of uterine activity with EHG and IUPC for at least 30 min. MAIN OUTCOME MEASURES: Number of uterine contractions detected by both EHG and IUPC (sensitivity). Number of contractions detected by EHG only [positive predictive value (PPV)]. Correlation between contraction amplitude and duration measured by EHG and IUPC. RESULTS: EHG detects uterine contractions accurately: sensitivity = 94.5% (95%CI: 87.5-100), PPV = 88.3% (95%CI: 76.2-100). The correlation of contractions' duration and amplitude between both methods is r = 0.31 (95%CI: 0.23-0.39) and r = 0.45 (95%CI: 0.38-0.52), respectively. CONCLUSIONS: EHG detects uterine contractions accurately during labour but the contraction's characteristics it measures are not directly comparable with that of IUPC.