[Measuring fetal vascular resistance with the Duplex scanner--a new fetal stress test].

In 77 women (phi 41 week, less than 7 days before delivery) we compared the resistance index (RI) in the umbilical artery (UA), descending aorta (DA) and intracranial artery (ICA) with an oxytocin challenge test (OCT) and a non stress test (NST). Proof criterias were asphyxia resulting in operative deliveries and metabolic acidosis. The sensitivity in predicting metabolic acidosis was low in all tests, but a high and comparable specificity could be achieved in both the RI and OCT. In predicting fetal asphyxia the RI in the ICA had a high sensitivity, the RI in the UA and DA had the highest specificity of all tests. Centralisation and increased brain perfusion seem to detect fetal asphyxia as a result of placental insufficiency.