The first of the two studies published showed that a mothers vaginal microbiome, an ecology of microorganisms in our body, ends up in the offspring's gut.
Using mice, they observed that changes to this microbiome brought on by stress altered the microbiome in the newborn's gut, leading to changes in the development of the brain.
"This mechanism could help us better understand how it may predispose individuals to neurodevelopmental disorders," said Tracy Bale, professor of neuroscience at UPenn.
Prenatal stress affected the levels of lactobacillus, a lactic acid-producing bacteria associated with brain neurochemistry and the gene expression, a process by which information from a gene is used in the synthesis of a functional gene product, in the hypothalamus.
In a parallel study, Bale and her team found that the O-linked-N-acetylglucosamine transferase or "OGT" protein in the placenta affected brain development.
By manipulating the OGT to mimic the effects of stress on the mother, they found that the babies were more sensitive to stress, very similar to the offspring of stressed mothers.
"These data also suggest that OGT may serve as a biomarker for a range of neurodevelopmental disorders in children, as we have previously shown similar regulation of this gene in human placental tissue," said Bale.