To study regional cerebral blood perfusion with power Doppler ultrasound (PDU) imaging in appropriate‐for‐gestational age (AGA) fetuses and those with intrauterine growth restriction (IUGR) at different hemodynamic stages of fetal deterioration.

Brain blood perfusion was studied with PDU imaging, and the fractional moving blood volume (FMBV) was estimated in 56 growth‐restricted and 56 AGA matched fetuses at 26–32 weeks of gestation. Fetuses with IUGR were classified according to progression of hemodynamic deterioration as follows: Group 1, abnormal umbilical artery (UA) pulsatility index (PI) (mean > 2 SD, n = 13); Group 2, abnormal UA‐PI and middle cerebral artery (MCA) PI (mean < 2 SD, n = 15); Group 3, abnormal UA‐PI, MCA‐PI and ductus venosus (DV) PI (mean > 2 SD) but atrial (a‐wave) flow present (n = 16); and Group 4, absent or reversed DV atrial flow (n = 12). FMBV was calculated in the complete mid‐sagittal, frontal, basal ganglia and cerebellar regions.

In all growth‐restricted fetuses, FMBV was significantly increased in all regions. Fetuses in Group 1 showed considerable increments in FMBV values in the frontal, complete mid‐sagittal and cerebellar regions, and a mild increase in the basal ganglia. From Groups 2 to 4, there was a steady reduction (compared with Group 1) in frontal FMBV values (F = 3.25, P = 0.027) together with a significant increment in the basal ganglia values (F = 11.61, P < 0.001). A trend for increasing FMBV values was also observed in the cerebellum, whereas a decreasing trend was noted in the complete mid‐sagittal area.

Brain perfusion in growth‐restricted fetuses shows clear regional variations, which change with progression of hemodynamic deterioration. After an initial and early increase in the frontal area, progression of fetal deterioration was rapidly associated with a pronounced decrease in frontal perfusion, together with an increase towards the basal ganglia. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.