Background and aims Small for gestational age neonates (SGA) living in conditions of chronic hypoxia during fetal life may develop different autoregulation mechanisms in cerebral perfusion in order to maintain oxygen delivery to the brain in comparison to appropriate for gestational age (AGA) neonates.
The aim of the current study was to estimate brain perfusion in SGA neonates during first postnatal week with the use of colour Doppler sonography.
Patients/methods Transcranial Doppler sonography from the temporal acoustic window was performed bilaterally with CX50 PHILIPS device using S8–3 transducer in the first, third and seventh day of life of SGA neonates with mean gestational age 31.6 ± 2.2w and to comparable AGA ones. Recorded parameters were Peak Systolic Velocity (PSV), End Diastolic Velocity (EDV), Mean Velocity (MV), Pulsatility Index (PI) and Resistance Index (RI) in middle cerebral artery MCA.
Results 26 SGA and 26 matched for GA control AGA neonates were prospectively enrolled with statistically significant difference in birth weight (1.201, 9 ± 369.1 vs 1.805, 3 ± 431.7, p < 0.0001), in head circumference (27.4 ± 2.8 vs 30.0 ± 2.4, p = 0.01) and haemoglobin in first postnatal day (17.7 ± 1.7 vs 15.9 ± 1.6, p < 0.0001). Fetal Doppler were pathological in 6 SGA neonates. Doppler study showed a gradual increase in PSV and MV during the first week bilaterally in both groups with statistically significant difference between them in MV in the third day (Right p = 0.017, Left p = 0.05). EDV in right MCA was also found higher in SGA neonates in the second measurement (p = 0.04). No statistically significant differences were found in the resume parameters.
Conclusion Increased brain metabolism in the first postnatal days is responsible for the observed augmentation of cerebral perfusion in order to maintain the balance between oxygen delivery and consumption. It seems that SGA neonates manage to develop compensatory mechanisms probably with an increase of their brain perfusion.