Using a transcutaneous Doppler technique we found a significantly lower cerebrovascular resistance and higher cerebral blood flow velocity indicating vasodilatation and increase of cerebral blood flow in small for gestational age infants compared with appropriate for gestational age infants during the first days of life. We speculate that these findings are due to a continuation of the fetal situation in which chronic hypoxia, mostly caused by pregnancy-induced hypertension, possibly causes a prostacyclin-induced vasodilatation.