A pregnant woman’s saliva may hold key to mental health, says MSU study

A pregnant person’s saliva can offer clues about their mental state, including whether they are experiencing anxiety, depression and post-traumatic stress disorder, according to a new study from Michigan State University.

The new research led by a Michigan State University professor of behavioral neuroscience concluded that the number and type of microbes present in the saliva of those who are pregnant are associated with stress and mental health in different ways from the gut microbiome or that found in people who are not pregnant.

“Positive mental health is crucial for mothers’ well-being and their ability to sensitively care for infants,” said Joseph Lonstein, professor in MSU’s Department of Psychology and lead researcher on the study. “We hope our study will stimulate future research on how microbes in and on our body, other than those in our gastrointestinal tract that are already often studied, are associated with mental health in mothers and even people who are not mothers.”

The study, published in the peer-reviewed open access journal BMJ Mental Health, included 224 pregnant women enrolled in the Michigan Prenatal Stress Study who were assessed for recent stresses and mental health symptoms during their second trimester.

MSU says the study was the first to look at the association between the type and number of microorganisms in the mouth and throat, also known as the oral microbiome, and maternal mental health.

Participants were asked to provide saliva samples during the week of their assessments, which showed the oral microbiome varied based on whether they had reported symptoms of life stress, anxiety, depression or post-traumatic stress disorder (PTSD), during the assessments.

Those women grouped as having symptoms of high trait anxiety or depression were found to have greater oral alpha diversity, indicating a higher number of microbe species within the sample size, while groups with high PTSD symptoms differed in beta diversity compared to participants with low PTSD symptoms, reflecting differences in community composition.

Additionally, specific stress and mental health traits were found to be associated with high levels of certain microbe species.

The study concluded that the oral microbiome could be a potential target for interventions to improve mental health during pregnancy.

“Successful targeting of the gut microbiome with probiotic treatment to improve maternal mental health could be extended in future studies to target oral cavity microbes through dietary changes, making recommendations for improving oral health, and probiotic treatments that might benefit mothers struggling with high life stress and poor mental health,” the study stated.