Use of Doppler technology in assessing fetal health

Doppler technology has provided new information about the fetus during intrauterine life. Changes in red cell velocity in the umbilical artery relate well to changes in downstream resistance in the placenta. Resistance (or more correctly impedance) appears to be closely linked to the number of small fetal arterioles in the tertiary stem villus. Placental pathology leading to a reduction in these arterioles is often associated with severe intrauterine growth restriction and poor perinatal outcome. Whilst there is no good evidence that screening women with low risk pregnancies is clinically useful, umbilical artery Doppler information would appear to be useful in the management of pregnancies already identified as at risk. Here abnormal Doppler findings suggest the need for maternal rest, increased fetal surveillance and early delivery when indicated.