Using Doppler ultrasound, cerebral blood flow velocities (CBFV) in the first month of life of normoxemic preterm infants born in the 28th gestational week with stable circulatory conditions were examined. The results were compared with fetal CBFV in the 28th to 32nd weeks of pregnancy. Peak systolic (PSV), end-diastolic (EDV) and time averaged maximum velocities (TAMV) were evaluated from the Doppler shifts recorded from the middle cerebral artery (MCA). Cerebral circulatory changes in neonates in the first 4 weeks of life were much more pronounced than in fetuses at the corresponding gestational age (28-32 weeks). After the rapid increase in neonatal CBFV in the first 3 weeks of life, our results appear to indicate a stabilisation between the 3rd and 4th week (corresponding to the 32 gestational weeks). The significance of, and possible mechanisms for, these changes are discussed.