Researchers have now confirmed through a new study that prenatal stress can change neural connectivity in the unborn baby's brain.

Confirming a long-held belief that stress during pregnancy is bad for the unborn kid, a new study has found that remaining stress-free during this period helps the brain development of the baby. A mother's stress during pregnancy changes neural connectivity in the brain of her unborn child, according to the study presented at a meeting of the Cognitive Neuroscience Society in Boston, Massachusetts.

"We have demonstrated what has long been theorised, but not yet observed in a human, which is that the stress of a mother during her pregnancy is reflected in connectional properties of her child's developing brain," said one of the researchers Moriah Thomason of Wayne State University in the US. Research in newborns and older children to understand prenatal influences has been confounded by the postnatal environment, Thomason explained. But recent advancements in foetal imaging allowed the researchers to gain insight into a critical time period in brain development never previously accessible.

Using foetal resting-state functional magnetic resonance imaging (fMRI), they examined functional connectivity in 47 human foetuses scanned between the 30^th and 37^th week of gestation. The researchers recruited the participating mothers from a low-resource and high-stress urban setting, with many reporting high-levels of depression, anxiety, worry and stress. They found that mothers reporting high stress had foetuses with a reduced efficiency in how their neural functional systems are organised.

The data suggests that the brain does not develop in a sequence from the simplest systems to more complex high-order systems, but perhaps instead first develops the areas that will be most critical in bridging across systems. The researchers found that the cerebellum played a central role in the observed effects, suggesting it may be especially vulnerable to the effects of prenatal or early life stress.