Abstract

It is estimated that 1 in 7 babies worldwide are born with low birth weight. In the majority of cases this is due to maternal malnutrition leading to intrauterine growth restriction (IUGR). Unless severe, IUGR is not life-threatening but it can affect metabolic health during adulthood. Interesting work on IUGR in the 1960s showed that the brain often scales down much less than other developing organs. This change in body proportions reflects a survival strategy called brain sparing, whereby the process that generates neurons (neurogenesis) is highly tolerant of malnutrition. Nevertheless, sparing is not perfect and can be associated with long-term neurological consequences. Brain sparing is shared across evolution, from humans to Drosophila fruit flies, and significant progress has been made in pinpointing its underlying protective mechanisms. Key advances have shown how the metabolism of neural stem cells, the cells driving neurogenesis, is well adapted to the stresses of malnutrition and hypoxia. New instruments for imaging metabolism with single-cell resolution now promise a step change in our understanding of brain sparing during IUGR and how it might best be treated.