Prenatal Stress Alters Infant Gut Microbiota

infant microbiome stress

Chronic maternal stress alters infant intestinal microbiota

Being pregnant can have enough stress of its own.  Yet, according to an article published in the journal Psychoneuroendocrinology, exposure to chronic maternal, prenatal psychological distress (PPD) alters infant intestinal microbiota.  Previous studies have also confirmed these observations.

Microbes as Stress Mediators

A recent prospective cohort study,  consisting of 398 mothers and their infants,  the most extensive study in the world to date, measured maternal PPD and its chronicity. 

The study used standardized questionnaires three times throughout the pregnancy of the participants.  The primary stress hormone indicated in hair cortisol levels were measured at early and mid-pregnancy.  Fecal samples of the infants were analyzed at two and a half months of age.

Elevated cortisol levels were associated with modifications in the infant microbiota. 

 Researchers concluded that elevated hair cortisol levels and chronic PPD are associated with modifications in the intestinal microflora of the infant, particularly increasing genera from gram-negative Proteobacteria phylum with potential pathogens.  The results also showed a negative correlation between chronic PPD and hair cortisol levels and bacteria concentrations from the Akkermansia genera and Lactobacillus.

The authors of this recent study indicate that “even though the literature on prenatal cortisol exposure is scarce, it can be interpreted that prenatal glucocorticoid exposure may affect gut physiology and immunity, and this may be reflected in the fecal microbiota composition.

Proteobacteria and inflammation 

Proteobacteria contain species that can cause increases in inflammation, as they harbour lipopolysaccharides that may play a role in psychopathology.  This may be associated with increased disease risk for children later in life, too.

The Benefits of akkermansia and lactobacillus spp on the infant microbiome

On the other hand, species from Akkermansia are considered beneficial for overall health, albeit in adults.  Thus, increased levels of Akkermansia may promote health in infants and even later during childhood development.  Increased abundance of Lactobacillus spp. in the infant microbiome was shown to be associated with lower cortisol levels; this bacteria is also considered to promote overall health.

Clinical Relevance

Expectant mothers want to be extra cautious when it comes to supplementation to help alleviate stress by avoiding specific excessive micronutrients, along with several botanicals and herbs, because there are many contraindications to be aware of during pregnancy.  Keeping this in mind, it may be essential that pregnant women focus on lifestyle and dietary measures for decreasing stress.  Pregnant women should receive adequate micronutrient intake from whole foods and reduce their consumption of processed foods and added sugars.

Expectant mothers should also incorporate some form of low-impact movement each day, which may be beneficial to lowering stress and cortisol.  Some of these low-impact movements may include walking, prenatal yoga or swimming.  In addition, implementing daily relaxation techniques may help prevent and/or reduce elevated cortisol levels.  These may consist of daily meditation practice, deep-breathing exercises, gratitude journaling and aromatherapy, which are all ways to support the central nervous system from “fight or flight” to “rest and digest” mode.  It is also essential to consider replacing chemically laden skin and hair care products and chemical household cleaning products with nontoxic products to reduce the body’s overall stress burden.

Prenatal Supplementation for a Healthy Stress Response

Some supplements that promote a healthy response to stress during pregnancy include vitamin B5 (pantothenic acid), magnesium glycinate, probiotics.  Pantothenic acid is involved in the synthesis of steroid hormones and the proper functioning of the adrenal glands, promoting relief of occasional or prolonged stressMagnesium plays a huge role in healthy nerve impulse conduction and muscle relaxation.  Research has also shown that magnesium reduces stress because it interacts with several neurotransmitter systems that impact the hypothalamic-pituitary-adrenal (HPA) axis.

Magnesium and the stress response 

Magnesium supplementation has significantly reduced cortisol concentrations and completely inhibited a rise in interleukin-6 inflammatory cytokine levels, favouring HPA activity.  Furthermore, it is well-established in the scientific literature that the gut-brain axis and microbiome significantly influence cognitive function, stress and neuroinflammation, among many other things. 

Probiotics and the HPA axis

 Animal studies have shown that pretreatment with a probiotic formula attenuated stress-induced HPA axis and nervous system activity,  “suggesting that probiotics modulate neuroregulatory factors and various signalling pathways in the central nervous system involved in stress response.”

In a randomized controlled trial of adults with stress and anxiety, 12 weeks of L. plantarum supplementation was shown to enhance the serotonin pathway, reduce cortisol levels, inflammatory cytokines, stress and anxiety symptoms, and improve cognitive functions.  Although the sample population was not pregnant in this study, the results show that probiotics, at least specific strains, may support healthy stress and mental health in pregnant women.

The research to date demonstrates the vital need for mothers to do their best to reduce exposure to stressors and find healthy ways to manage stress for the sake of their infant’s health.  In recapitulation, expectant mothers may utilize a nutrient-rich diet, lifestyle changes and supplements as tools to lower stress for a healthy pregnancy.  Magnesium, vitamin B5, probiotics are great options while pregnant that may help expectant mothers achieve a calmer and more relaxed mind.

By Caitlin Higgins, MS, CNS, LDN