Clinical use of assessing regional brain circulation perfusion to identify long term neurodevelopmental anomalies in small for gestational age fetuses (SGA)

PI: Dr. E. Gratacós
Funding Agency: Thrasher Research Fund
Duration: 2009-2012

Preliminary data suggest that growth restricted fetuses with brain injury show during pregnancy a so-called “regional brain redistribution” of blood supply, whereby more blood is directed to certain brain regions, mainly the frontal areas. This adaptive mechanism reflects that the baby is starting to suffer a significant restriction of oxygen and nutrients and tries to compensate it directing more blood to critical brain areas. The existence of this phenomenon opens important opportunities. Firstly, if we could identify which fetuses have increased brain blood supply  we would have means to diagnose the onset of brain injury. Secondly, identifying fetuses at risk would allow to evaluate which brain areas are more affected. Thus, significant advances in our current understanding of the prenatal origins of brain injury in children could be made.

We have described that a simple Doppler ultrasound exam of the blood circulation in two fetal brain blood vessels, anterior and middle cerebral arteries, could identify increased brain blood supply and thus fetuses at highest risk for brain injury. We propose a large study to confirm these findings and to understand the mechanisms leading to brain damage in children born SGA.

In a great number of children with neurological problems, brain damage occurred before birth. One of the main risk factors for brain damage is intrauterine growth restriction (IUGR), which occurs in up to 7% of pregnancies. Traditionally, research has been focused on the most severe, early-onset forms. In contrast, moderate forms of IUGR, normally defined as small for gestational age (SGA), which actually constitute the vast majority of cases, were considered to have a good prognosis. However, recent studies have shown that up to 30-50% might present abnormal neurodevelopment later in childhood. Most of these abnormalities are cognitive disorders, they are not immediately apparent to families, or even to pediatricians, but they will produce major learning and social disabilities in childhood. The awareness on this fact is still small among clinicians, and in any case there are no diagnostic means to identify fetuses at risk. The mechanisms and the type of brain injury in these fetuses are largely unknown.