Objective: To assess the value of incorporating continuous wave Doppler ultrasound of the uterine arteries into the routine scan as a screening test in an unselected population.
Design: A cross sectional study by multiple operators using continuous wave Doppler ultrasound to obtain flow velocity waveforms (FVW) from both uterine arteries of all women attending for routine anomaly scan at 18 to 22 weeks over a period of 12 months. An abnormal FVW in either uterine artery was used to predict intrauterine death, antepartum haemorrhage and three different degrees of severity of pre-eclampsia and growth retardation, singly and in combination.
Setting: King's College Hospital, London.
Subjects: Two thousand, four hundred and thirty women attending for routine anomaly ultrasound scan.
Results: A total of 2430 women were scanned with a 90% follow up rate. The results demonstrate higher sensitivities than previous studies, but with a high proportion of false positive tests. By including an early diastolic notch in the definition of an abnormal FVW the prediction of pre-eclampsia is markedly improved; the relative risk to a woman with an abnormal waveform of developing moderate or severe pre-eclampsia is increased 24-fold. Although the positive predictive value for babies less than the 5th centile for gestation is only 15%, those at risk of neonatal complications may be identified.
Conclusion: This simple test can be performed at a routine visit and a group of women can be identified for further assessment and possible therapeutic intervention.