Lactobacillus rhamnosus HN001 reduces postpartum depression

A probiotic taken by women during the second and third trimesters and, if breastfeeding, during the first 6 months after childbirth was found to reduce depression and anxiety scores during the postpartum period (Slykerman et al. 2017). The strain of probiotic used in this study was Lactobacillus rhamnosus HN001 administered daily at 6x10e9 cfu/day. To be eligible for the study, one parent of the unborn child needed to have a history of asthma or eczema.

This is the first study to test the impact of a probiotic on psychological symptoms during the postpartum period. Importantly, these probiotics have been shown to be safe and well-tolerated for this use, and this study documents their effectiveness as well.

The idea that gut microbes are associated with psychological symptoms is supported by observational (microbiota patterns among people with anxiety and depression differ from healthy controls) and mechanistic (mediated by the microbiota-gut-brain axis) studies. This study by Slykerman et al. 2017 adds to the short but growing list of human studies that demonstrate that certain strains of probiotics may help manage certain psychological symptoms. (See past posts, listed below.)

Some human studies that have evaluated psychological symptoms have not shown a benefit to probiotics, stressing the importance of further studies to determine populations most likely to benefit, probiotic strains most likely to be effective and symptoms that are most likely to be improved.

Some details of this study are of interest. This study used a much larger sample size than other studies of psychological symptoms. Further, unlike other studies of pregnant women, the intervention was started much earlier in pregnancy. One possible confounder in the study is that mothers completed the psychological symptom questionnaires 1 to 2 months after delivery, which would report memory of these earlier symptoms and not symptoms as they were being experienced. This finding was from a secondary objective* of the study (full protocol and rationale for this study published Barthow et al. 2016). Finally, fully restricting probiotic consumption by study subjects was difficult, as probiotics are increasingly available in foods and drinks and the study was long-term (18 months).

To conclude, this study suggests that a daily dietary supplement can make a meaningful difference in postpartum symptoms. A probiotic approach to help manage postpartum depression may impact not just maternal quality of life, but also long-term consequences for the infant. Further, an effective probiotic may offer an alternative to drug treatments, which have side effects and are not favored by breastfeeding mothers.


*Briefly, the objectives of the study were:

  • Primary objectives were related to the infant
    • Eczema and atopic sensitization at infant age of 1 year
  • Secondary objectives were related to the mother (maternal health outcomes)
    • Gestational diabetes mellitus
    • Bacterial vaginosis
    • Group B Streptococcal vaginal colonization
    • Depression and anxiety postpartum



Slykerman RF, Hood F, Wickens K, Thompson JMD, Barthow C, Murphy R, Kang J, Rowden J, Stone P, Crane J, Stanley T, Abels P, Purdie G, Maude R, Mitchell EA; Probiotic in Pregnancy Study Group. Effect of Lactobacillus rhamnosus HN001 in Pregnancy on Postpartum Symptoms of Depression and Anxiety: A Randomised Double-blind Placebo-controlled Trial. EBioMedicine. 2017 Sep 14. pii: S2352-3964(17)30366-3. doi: 10.1016/j.ebiom.2017.09.013. [Epub ahead of print]

Barthow, C., Wickens, K., Stanley, T., et al., 2016. The Probiotics in Pregnancy Study (PIP Study): rationale and design of a double-blind randomised controlled trial to improve maternal health during pregnancy and prevent infant eczema and allergy. BMC Pregnancy Childbirth 16, 133.

Trial registration

Previous trial by this same research group with similar design:


Wickens K, Stanley TV, Mitchell EA, Barthow C, Fitzharris P, Purdie G, Siebers R, Black PN, Crane J. Early supplementation with Lactobacillus rhamnosus HN001 reduces eczema prevalence to 6 years: does it also reduce atopic sensitization? Clin Exp Allergy. 2013 Sep;43(9):1048-57

Other posts on brain activities of probiotics:

Can Probiotics Help Your Brain? February 5, 2013

2017 ISAPP Annual Meeting Highlights September 22, 2017

Probiotic Reduces Anxiety April 29, 2016

Fermented Food Consumption and Social Anxiety June 3, 2015

Can Gut Microbes Change Your Eating Behavior? January 21, 2015

Health Benefits of Fermented Foods June 21, 2016