Can Probiotics Improve Mental Health Outcomes in Pregnant Women with Obesity?

Research Paper Title

Probiotics and Maternal Mental Health: A Randomised Controlled Trial among Pregnant Women with Obesity.


Poor maternal mental health has been associated with a myriad of pregnancy and child health complications.

Obesity in pregnancy is known to increase one’s risk of experiencing poor maternal mental health and associated physical and mental health complications.

Probiotics may represent a novel approach to intervene in poor mental health and obesity.


The reseaschers conducted this pre-specified secondary analysis of the Healthy Mums and Babies (HUMBA) randomised controlled trial to investigate whether probiotics would improve maternal mental health outcomes up to 36 weeks of pregnancy.

Two-hundred-and-thirty pregnant women with obesity (BMI ≥ 30.0 kg/m2) were recruited and randomised to receive probiotic (Lactobacillus rhamnosus GG and Bifidobacterium lactis BB12, minimum 6.5 × 109 CFU) or placebo capsules.

Depression, anxiety, and functional health and well-being were assessed at baseline (120-176 weeks’ gestation) and 36 weeks of pregnancy.


Depression scores remained stable and did not differ between the probiotic (M = 7.18, SD = 3.80) and placebo groups (M = 6.76, SD = 4.65) at 36 weeks (p-values > 0.05).

Anxiety and physical well-being scores worsened over time irrespective of group allocation, and mental well-being scores did not differ between the two groups at 36 weeks.


Probiotics did not improve mental health outcomes in this multi-ethnic cohort of pregnant women with obesity.


Dawe, J.P., McCowan, L.M.E., Wilson, J., Okesene-Gafa, K.A.M. & Serlachius, A.S. (2020) Probiotics and Maternal Mental Health: A Randomised Controlled Trial among Pregnant Women with Obesity. Scientific Reports. 10(1), pp.1291. doi: 10.1038/s41598-020-58129-w.

Sickness: In the Mind or Gut?

“Remember the last time you had a stomach bug and just wanted to crawl into bed and pull up the covers?

That is called “sickness behaviour” and it is a kind of short-term depression.

The bacteria infecting you aren’t just making you feel nauseous, they are controlling your mood too.

It sounds absurd: they are in your gut and your feelings are generated in your brain.

In fact, this is just an inkling of the power that microbes have over our emotions.

In recent years, such organisms in the gut have been implicated in a range of conditions that affect mood, especially depression and anxiety.

The good news is that bacteria don’t just make you feel low; the right ones can also improve your mood.

That has an intriguing implication: one day we may be able to manipulate the microbes living within our gut to change our mood and feelings.

It is early days, but the promise is astounding.

The World Health Organization rates depression and anxiety as the number one cause of disability, affecting at least 300 million people worldwide.

The new findings challenge the whole paradigm of mental illness being caused by a chemical imbalance in the brain, and offer an alternative to drug treatment.

You’ve probably heard of probiotics, but these are their new incarnation – psychobiotics. They could be about to change the mood of the planet.” (Anderson, 2019, p.34).


Anderson, S. (2019) The Pyschobiotic Revolution. New Scientist. 07 September 2019.