Regional distribution of cerebral blood flow in experimental intrauterine growth retardation.

The regional distribution of cerebral blood flow was assessed in eight control and eight morphometrically growth-retarded fetal lambs to determine whether perfusion patterns within the cerebral circulation are altered in this model of intrauterine growth retardation. Growth retardation was induced by repetitive embolization of the uterine circulation, and flow distribution was assessed by use of microspheres. Distribution to 22 separate areas, expressed as a flow/weight ratio, was virtually identical in the two groups. Cortical gray matter received 56% of total cerebral flow, and cortical white matter received 7%. However, flow X gm-1 in cortical white matter was 85% of that in cortical gray matter. We conclude that perfusion patterns within the cerebral circulation are not altered in this model of intrauterine growth retardation and that, compared to gray matter, cortical white matter has a high flow X gm-1 in fetal life.