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Maternal stress, vaginal microbiota composition, gut microbiome of the newborns and normal neurodevelopment (2015-12-21)

Stress during the first trimester of pregnancy alters the population of microbes living in a mother’s vagina. Those changes are passed on to newborns during birth and are associated with differences in their gut microbiome as well as their brain development, according to a new study by University of Pennsylvania researchers.

Researchers hypothesize that maternal stress alters vaginal microbiota composition, and the vertical transmission of this dysbiotic community may promote distinct bacterial colonization patterns in the offspring gut, impairing the metabolism, availability and use of nutrients necessary for normal neurodevelopment in a sex-specific manner.

During a vaginal birth, a newborn is exposed to its mother’s vaginal microbes which importantly colonizes the newborn’s gut, helping its immune system mature and influencing its metabolism. These effects take place during a critical window of brain development.

Babies born by C-section miss out on this initial exposure and are more likely to be exposed to and their guts then colonized by other bacteria in the local environment, including the mother’s skin and potential pathogens in the hospital.
Interestingly, a subset of offspring that were delivered by C-section and then had their mother’s vaginal microbiota introduced to their gut ultimately had gut microbiota that resembled that of vaginally-delivered offspring.

The new work, published in Endocrinology, suggests that the maternal vaginal microbiome is one of the ways that a mother’s stress during pregnancy can “reprogram” the developing brains of her children.

One implication is that these changes could put the offspring at an increased risk of neurodevelopment disorders such as autism and schizophrenia, neurodevelopmental disorders where disruption of gut microbiota and gastrointestinal dysfunction are increasingly reported.

The fact that male offspring appeared most affected may have implications for the development of disorders such as autism and schizophrenia, both of which disproportionately affect males.

Tracy Bale, senior author on the study is a professor of neuroscience in Penn’s School of Veterinary Medicine and Perelman School of Medicine. In addition to Bale, the study was conducted by postdoctoral researchers Eldin Jašarevic and Christopher Howerton and research specialist Christopher Howard, all from Penn Vet.

“These studies have enormous translational potential,” Bale said. “Many countries are already administering oral application of vaginal lavages to C-section delivered babies to ensure appropriate microbial exposure occurs. Knowledge of how maternal experiences such as stress during pregnancy can alter the vaginal microbiome is critical in determination of at-risk populations.”

The research was supported by the Penn Vet Center for Host-Microbial Interactions, the National Institute of Mental Health, the CHOP Metabolomics Core, Perelman School of Medicine Proteomics and Systems Biology Core, and the Next Generation Sequencing Core.

For more information
Alterations in the Vaginal Microbiome by Maternal Stress Are Associated With Metabolic Reprogramming of the Offspring Gut and Brain

Penn - University of Pennsylvania