Maternal Stress, Autism and a Possible Preventative Probiotic Treatment?

A few weeks back, a study came out of the University of Colorado, Boulder, which is worth reporting.[i]  It is one in a long line of similar studies which show that exposure to our “old friends” modulates the immune system in such a way as to lower inflammation levels thereby positively impacting the central nervous system and brain development.

On the other hand, it is one of only a handful of studies that show that using probiotics during pregnancy may make a profound difference in lowering the risk of autism.

I’ve written many times before (here is just one example) about maternal immune activation (MIA):  when the immune system is fighting something off and generates an excessive inflammatory response which has an adverse effect on the fetus.  Just how adverse, no one  yet knows for sure entirely, but research has indicated that it can greatly increase the risk of immune mediated illnesses in children, including autism.  If you’ve learned nothing else reading this blog over the years, you know that the lack of biome diversity has led our immune systems to be hyper vigilant – over reactive – to both ourselves (autoimmune disease) and benign non-self (i.e. allergic response).  We have low levels of regulatory T-cells and cytokines; our off-switches are broken.  And that, in turn, is having profound effect upon our children.

In this study, the researches specifically looked at how to potentially alleviate the effects of stress(which you know is highly inflammatory) during pregnancy on infants.  In previous work, the lead researchers, Dr. Daniel Barth, had shown that when stressed rats are given a drug called terbutaline (a medicine commonly used to prevent preterm labor), the pups demonstrate autism-like behaviors, including social deficits and repetitive behaviors.  They also develop seizures.  The  researchers exposed rats to mild stress, gave them terbutaline – and then half the animals were injected with heat-killed Mycobacterium vaccae, which I have written about a couple of times before.  (This post is about using this to vaccinate against PTSD and this one is more about its anti-stress effects.)  (In previous work, this has been shown to have long-lasting anti-inflammatory effects on the brain.)  The pups were then tested at 2 and 4 months.

As per previous research, the control group (not given the probiotic vaccine) demonstrated clear autism-like behaviors, whereas the pups in the experimental group did not:  “Immunization with M. vaccae appears to provide some protection against the negative effects of environmental stressors during development, specifically against Autism Spectrum Disorder (ASD)-like behavior.”[ii]

A few key lines from the paper:  “The propensity for microbial-based therapies to alleviate ASD-like behavior has been demonstrated in several animal models.  These data not only support the emerging role for microbe-immune interactions in neurodevelopmental disorders like ASD, but also inspire therapeutic possibilities….M. vaccae has proven successful in immunizing against the inflammatory effects of chronic stress both peripherally and, a prospect made more promising by recent results indicating the safety of heat-killed M. vaccae immunotherapy in human trials….the current data suggest it may be possible to immunize against ASD when stress and inflammatory components are a precipitating factor.”


Strangely, the inoculation did not protect against the development of seizures.  The researchers believe this may be simply because they did not treat the mothers for long enough, and they plan on retesting this in the future.  I’ll watch for those results, of course.

The researchers hope that this work may someday provide a means of treating at-risk moms a treatment, in the form of a probiotic or inoculation, to protect their babies.  Ultimately, of course, this research teaches us – yet again- that detrimental effects of biome depletion on humans cannot be overstated.  The researchers themselves state that “…mothers should be cognizant of the potential risks of emotional and environmental stressors…” and should “…try to expose themselves to beneficial bacteria through fermented foods like yogurt and sauerkraut, and even time spent in nature.”


[i] Smith, ZZ, et. al. Effects of immunization with heat-killed Mycobacterium vaccae on autism spectrum disorder-like behavior and epileptogenesis in a rat model of comorbid autism and epilepsy. Brain, Behavior and Immunity. 2020.


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