Objective: To compare cardiotocograph (CTG) records during labour in cases of neonatal encephalopathy and matched controls.
Design: Case-control study.
Setting: Metropolitan area of Perth, Western Australia.
Subjects: Term deliveries complicated by neonatal encephalopathy and controls matched for sex, hospital, time of birth, day of week of birth and maternal health insurance.
Main outcome measures: Low fetal heart rate (FHR) variability, FHR accelerations, late decelerations, total Kreb's score and FIGO classification of CTG records.
Results: The neonatal encephalopathy group had significantly more abnormal CTG records (89%) classified according to FIGO, although 52% of control CTG records were also abnormal. CTG records from cases developed significant differences in terms of absence of FHR accelerations and low FHR variability, but not late decelerations, prior to delivery.
Conclusion: Given the low incidence of neonatal encephalopathy in this study (7 per 1000) the predictive value of an abnormal CTG record is clinically unhelpful. However, the changes in the FHR in such cases suggest a greater disturbance of fetal (rest-activity) behaviour during labour.