The AEDV in the umbilical artery or the foetal aorta is considered to be the most severe waveform abnormality. Using pulsed Doppler, we found such a waveform in 51 foetuses out of 954 high-risk pregnancies (33/51 in both vessels, 17/51 aorta only and 1/51 umbilical artery only). A reverse flow was registered in 24 foetuses. The outcome was compared with that of a control group (n = 72) showing normal Doppler findings. The following parameters were highly significant (p less than 0.001): Rate of Caesarean section owing to foetal distress (85.3% to 4.8%), of growth retardation (IUGR) (66.7% to 6.0%), of premature delivery (73.5% to 7.5%), of low postnatal pH- and Apgar score (73.5 to 12.1%), of admission to the neonatal intensive care unit (94.1% to 8.6%), of morbidity (35.3% to 2.3%) and of mortality (41.1% to 0%). We observed 17/51 intrauterine and 4/51 postnatal deaths. The rate of malformations was 35.3% with 4 cases of aneuploidy. Considering the malformations, the rate of corrected mortality was 23%. We found, that the association of an AEDV and the absence of severe IUGR is highly suspicious of malformation. We also observed, that congenital heart diseases (CHD) could lead to an AEDV too. An AEDV precedes a pathological cardiotocogram (CTG) with a latency of 0 to 35 days (mean 9.5 days). This latency is not predictable, but we think, that a reliable assessment of jeopardy is possible by analysing further vessels (Aa. arcuatae, A. renalis, A. carotis interna): 72.5% of the foetuses with AEDV had high indices in the carotid artery and 93.1% among these showed a pathological CTG pattern.(ABSTRACT TRUNCATED AT 250 WORDS)