Large births bode ill for brains

U. SOUTHAMPTON (UK) — Children who are born small with relatively bigger placentas show more activity on the right side of their brain than their left, a pattern linked to mood disorders, including depression.

The findings, published online in the journal PLoS One, adds to a growing body of evidence showing that adverse environments experienced by fetuses during pregnancy (indicated by smaller birth size and larger placental size) can cause long-term changes in the function of the brain.

“The way we grow before birth is influenced by many things including what our mothers eat during pregnancy and how much stress they are experiencing,” says Alexander Jones, an epidemiologist at the University of Southampton, who led the study.

“This can have long-lasting implications for our mental and physical health in later life,” Jones says. “This is the first time we’ve been able to link growth before birth to brain activity many years later. We hope this research can begin to shed new light on why certain people are more prone to diseases such as depression.”

The neurological responses of 140 children from Southampton, aged between eight and nine, were monitored for the study.

Tests evaluated blood flow to the brain in response to increased brain activity, exposing differences in the activity of the two sides. Measurements were taken of tiny fluctuations in the temperature of the tympanic membrane in each ear, which indicate blood flow into different parts of the brain.

Disproportionate growth of the placenta and the fetus is thought to occur in pregnancies where the mother has been experiencing stress or where there have been problems with the availability of nutrients.

Previous research has linked this pattern of growth to other diseases such as hypertension and greater physical responses to stress in later life.

More news from the University of Southampton: