Randomised comparison of routine versus highly selective use of Doppler ultrasound in low risk pregnancies

Abstract

Objective: To help answer the question: should Doppler ultrasound of the umbilical circulation be made available to all pregnant women as part of their routine antenatal care?

Design: A randomised trial.

Setting: St James's University Hospital, Leeds.

Subjects: 2025 low risk primigravid women.

Main outcome measures: Obstetric intervention rates and short term neonatal morbidity.

Results: The incidence of abnormal Doppler was low (1.7%) with complete absence of end diastolic flow in only 0.3% of cases. No significant differences could be demonstrated between control and study women in any of the outcomes measured.

Conclusion: This study did not demonstrate any benefit or harm from Doppler ultrasound as a routine screening test for all low risk women, whereas our previous studies have suggested that it is useful in high risk pregnancies. Any marginal returns on extending access to Doppler ultrasound from high risk to all women must be small. Since this test has excellent performance characteristics (sensitivity and specificity) for the prediction of fetal hypoxia and acidosis our results call into question the cost to benefit ratio of all tests designed to predict these outcomes in low risk women.