The maternal and fetal placental circulation was studied by recording of the blood flow velocity waveforms (FVW) of the uterine and umbilical artery (UFVW and UmbFVW) in 99 pregnant women. The FVW was quantitated by the Pulsatility-Index (PI). By analysing the UFVWs as well as the UmbFVWs, it was possible to define four groups of patients, based on normal versus abnormal PI on either side of the placenta. The group with abnormal FVWs on both sides of the placental bed showed the highest percentage of pathological phenomena. Uterine and/or umbilical artery FVW analysis was not sensitive in the prediction of small for gestational age (SGA), whereas it was a sensitive method for the prediction of fetal distress (FD) during pregnancy. For the latter, our data suggested that at a chosen specificity of 95%%. FVW analysis on both sides of the placental bed was more sensitive than separate UFVW or UmbFVW analysis.