Abnormal Doppler in the middle velocimetry and blood flow volume cerebral artery in very severe intrauterine growth restriction: is the occurrence ofreversal of compensatory flow too late?

Objectives To determine the time course of quantified volumetric flow and p ulsatility index changes in the middle cerebral arteries of severe intraute rine growth restricted fetuses with absent or reversed end diastolic flow v elocities (AREDFV) on umbilical artery Doppler with a view to defining the threshold for early intervention before the onset of reversal of adaptation . Setting Fetal growth clinic of a large UK teaching hospital. Sample Seventeen severe intrauterine growth restricted (AC < third centile for gestation and gender) fetuses with abnormal umbilical artery Doppler ve locimetry and oligohydramnios (amniotic fluid index < third centile for ges tation). Methods One to three daily Doppler velocimetry and quantified volume flow o f the middle cerebral artery Doppler velocimetry of the umbilical arteries and daily cardiotocography. Results Reversal of adaptation occurred in eight fetuses, four of which end ed as stillbirths and four as neonatal deaths. In two of these fetuses, thi s had already occurred before the diagnosis of intrauterine growth restrict ion. In the others, the onset was rapid and difficult to predict. Volume fl ow in the middle cerebral arteries decreased in those fetuses exhibiting re versal of adaptation but rose in the nine in which compensatory Doppler ind ices persisted. The decrease in volume flow occurred before the onset of re versal of adaptation in the pulsatility index. In the fetuses exhibiting re versal of adaptation, the rise in the pulsatility index was consistent over 48 hours compared with the physiological fluctuations in pulsatility index in some fetuses where the rise was only for 24 hours followed by a fall. Q uantified volume flow fell in the fetuses before reversal of adaptation set -in. The umbilical artery Doppler indices fluctuated between absent and rev ersed end diastolic velocities within the same fetus irrespective of the ch anges in the middle cerebral artery Doppler indices. Conclusion Reversal of adaptation is of sudden onset and is associated with poor prognosis. Predicting its occurrence on Doppler indices is difficult as the changes may be very rapid. However, volume flow changes appear to be slower and of earlier onset than the pulsatility index changes. This may t herefore be a more useful tool in predicting imminent reversal of adaptatio n and therefore early delivery.