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Updated: Aug 24, 2026

Non-invasive Optical Measurement of Cerebral Metabolism and Hemodynamics in Infants
Published on: March 14, 2013
Doppler examination of the middle cerebral artery in anemic fetuses
S Vyas1, K H Nicolaides, S Campbell
1Harris Birthright Research Centre for Fetal Medicine, Department of Obstetrics and Gynaecology, King's College School of Medicine, London, England.
In 24 red cell isoimmunized pregnancies the fetal middle cerebral artery mean blood velocity increased with anemia. The blood velocity was not related to fetal blood PO2 and the relation of increased velocity to anemia was not affected by the pulsatility index. These findings suggest that the hyperdynamic circulation is a consequence of decreased blood viscosity.
In 24 red cell isoimmunized pregnancies the fetal middle cerebral artery mean blood velocity increased with anemia. The blood velocity was not related to fetal blood PO2 and the relation of increased velocity to anemia was not affected by the pulsatility index. These findings suggest that the hyperdynamic circulation is a consequence of decreased blood viscosity.

