Continuation of normal neurobehavioural development in fetuses with absent umbilical arterial end diastolic velocities.

Detailed serial observations of behaviour were made in four singleton fetuses who were very small for dates and who had persistently absent umbilical artery end diastolic velocities for 2 to 9 weeks duration. All were born preterm for deteriorating maternal disease, and in two there were additional fetal indications for delivery. Behavioural comparison with 45 low risk singleton fetuses, at comparable gestations, revealed no significant differences in the development of behavioural cycles, the proportion of time spent in quiet cycles, or the amount of fetal breathing. None of the fetuses developed an abnormal heart rate pattern. We conclude that prenatal neurobehavioural development may continue apparently unimpaired in the presence of absent umbilical artery end-diastolic velocity of several weeks duration. Long term data of infant outcome are necessary before the clinical significance of this can be assessed.