Mother’s Childhood Adversity Leaves Imprint on Children’s Microbiome Interview with:

Dr. Callaghan

Bridget Callaghan Ph.D.

Assistant Professor of Psychology
Dr. Callahan studies interactions between mental and physical health across development. What is the background for this study?

Response: A growing body of evidence links the gut microbiome to brain and immune functioning, and changes to that community of microorganisms is likely among the ways that hardship affects children’s socioemotional development.

Limited evidence in humans has demonstrated the adversities experienced prenatally and during early life influence the composition of the gut microbiome, but no studies had examined whether stress experienced in a mother’s own childhood could influence the microbiome of the next generation of children. What are the main findings?

Response:  In the current study, we examined the transgenerational effects of adversity on the gastrointestinal microbiome of second generation children when they were 2 years old. We observed that a mothers own experience with adversity during her childhood (maternal childhood maltreatment), maternal prenatal anxiety and depression symptoms (prenatal adversity), and postnatal adverse life events that had occurred from the second generation child’s birth until they were 2 years old (postnatal adversity), each had unique influences on the species contained in the 2 year old child’s microbiome. In other words, events that had occurred to the mother decades earlier were detectable in her children’s microbiome.

Children who experienced prenatal adversity had microbiomes in which the species of microorganisms had populations of similar sizes, a metric biologists call “evenness,” which had not been found before. Typically, the populations of the various species that make up the gut’s microflora are “lumpier,” with some species being abundant and others less common. In the study sample, however, those differences were less prominent, and populations were of similar sizes.

The gut microbes of children who experienced more postnatal adversity also had less genetic diversity, meaning that the microbes living in each child’s gut were more closely related to each other than such microbes usually are. What should readers take away from your report?

Response: We have known for some time that effects of adversity tend to persist across generations, with effects of parent’s own childhood experiences being detected in stress hormones, behavior, and brains of their children. Here we are seeing the effects of parent’s early adversity also being reflected in their children’s gut microbiome. Knowing this information can provide important insights into ways we might arrest intergenerational transmission of adversity effects. However, the microbiome is likely just one piece of this large and complicated puzzle. What recommendations do you have for future research as a results of this study?

Response: In this study, we were investigating the composition or structure of the microbiome in young children, but the function of the microbiome – what can these organisms potentially do – is a very important next question. Many of the species we found to be related to adversity are known to interact with the immune system in some way, suggesting that maybe the way the gut microbiome interacts with the immune system is different after adversity. This hypothesis can and should be tested in future studies that home in on the functional potential, not just composition, of the microbiome. Is there anything else you would like to add? Any disclosures?

Response: This study focused on mothers as those were the data that were available in this cohort (Growing Up in Singapore Towards Healthy Outcomes – GUSTO). Scientific research on children and families still struggles to gain equal participation by fathers. Although there are well described pathways via which the microbiome of mothers can be ‘vertically’ passed onto their children (e.g., vaginal birth, breastfeeding), there are many different routes through which the experiences of parents, not just mothers, could affect their children’s microbiome. We suspect that father’s adverse experiences during childhood, and his mental health during the prenatal period, may also have indirect effects on children’s microbiome, but this remains to be tested.

This project was made possible by collaborators on the GUSTO project, and the parents and children who contributed their data. 

None of the authors have any disclosures to report. 

Citation: Querdasi FR, Enders C, Karnani N, Broekman B, Yap Seng C, Gluckman PD, Mary Daniel L, Yap F, Eriksson JG, Cai S, Chong MF, Toh JY, Godfrey K, Meaney MJ, Callaghan BL. Multigenerational adversity impacts on human gut microbiome composition and socioemotional functioning in early childhood. Proc Natl Acad Sci U S A. 2023 Jul 25;120(30):e2213768120. doi: 10.1073/pnas.2213768120. Epub 2023 Jul 18. PMID: 37463211.


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Last Updated on July 25, 2023 by Marie Benz MD FAAD