Cerebral Doppler measurements seem to be a future method to evaluate the degree of fetal hypoxemia. The aim of this study was (1) to elaborate standard curves for the different cerebral vessels in our own population, and (2) to describe the predictive value of Doppler measurements for intrauterine growth retardation (IUGR) and fetal acidosis. We recorded cerebral flow velocity waveforms from 71 normal pregnancies to establish standard curves for the following vessels: proximal middle cerebral artery, distal middle cerebral artery and posterior cerebral artery. Finally, we calculated the cerebroplacentar index (CPI) for each case. The predictive values from the different vessels were determined in 24 patients with IUGR and 17 cases with fetal acidosis. The poor sensitivity and the low positive predictive value of each cerebral vessel is probably explained by the rather long interval between the last Doppler assessment and delivery (22 +/- 23 days). Reducing the interval to less than 7 days, the distal middle cerebral artery and the CPI were pathological in 4 cases out of 5 fetuses that underwent cesarean section for fetal distress. These latter results have encouraged us to use cerebral Doppler flow velocity to detect fetal hypoxemia. In conclusion, the middle cerebral artery blood flow in its distal part seems to be the finest parameter to predict fetal acidosis, and this vessel should be used to optimize obstetrical management of high-risk pregnancies.