Screening for fetal distress in labour using the umbilical artery blood velocity waveform

OBJECTIVE: To investigate the potential value of umbilical artery blood velocity wave-form measurement as a screening test for intrapartum fetal distress on admission to the labour ward. DESIGN: Prospective study drawn from the local population of pregnant women. SETTING: The labour ward of the Princess Anne Hospital, Southampton, UK. SUBJECTS: 334 women with singleton pregnancies of at least 37 weeks gestation. MAIN OUTCOME MEASURE: Emergency caesarean section for fetal distress. RESULTS: There was a twelve-fold increase in the rate of emergency caesarean section for fetal distress (95% Confidence Interval (CI), 4.9-29) among women with a systolic/diastolic (S/D) ratio > or = 3.0, when compared to those with an S/D ratio of < 3.0 (P < 0.00001). Measurement of the umbilical artery blood velocity waveform compared favourably with admission cardiotocography. CONCLUSIONS: Umbilical artery blood velocity waveform analysis may be used to screen for fetal distress in labour and appears to be particularly sensitive to problems of placental origin. However, it is not likely to confer benefit in labour wards whose fetal heart rate monitoring policy is determined by pregnancy risk factors and admission cardiotocography.