Computerised analysis of the fetal heart rate and relation to acidaemia atdelivery

Objective To identify the individual features of the computerised analysis of the cardiotocograph that relate to arterial pH and base deficit at deliv ery. Design Retrospective observational study. Setting Teaching hospital labour wards. Participants 679 woman requiring continuous intrapartum fetal monitoring. Methods Fetal heart and uterine contraction data were obtained using the No ttingham Fetal ECG monitor. Fetal heart rate, patterns for the last half-ho ur preceding delivery were analysed using a computer algorithm developed fo r intrapartum. application. The significance of the areas under receiver op erator characteristic curves were calculated. Main outcome measures Umbilical arterial pH and base deficit at delivery. Results Three parameters, fetal bradycardia, total deceleration area and th e deceleration area after a contraction had receiver operator characteristi c curves that significantly predict a low umbilical arterial pH and base de ficit at delivery (areas under receiver-operator characteristic curves = 0. 53, SD 0.01 P = 0.03; 0.60, SD 0.03 P = 0.002; 0.62, SD 0.04 P < 0.001, res pectively). Tachycardia, accelerations and variability did not. Conclusions. The individual components of the computerised analysis of the fetal heart rate that predict acidaemia at delivery are identified.