SCREENING FOR FETAL DISTRESS IN LABOR USING THE UMBILICAL ARTERY BLOOD VELOCITY WAVE-FORM

Objective To investigate the potential value of umbilical artery blood velocity waveform 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 twelvefold 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 greater-than-or-equal-to 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.