The last several years have brought about amazing new insights into the infant microbiome – the microorganisms that make up baby’s body, especially his gut. The gut is the home of the immune system, and a good start as an infant can set a person up for a lifetime of good health.

The colonization of a baby’s gut may begin even before birth, and can be affected by things such as maternal diet, maternal weight in pregnancy, premature birth, birth method (vaginal versus cesarean), antibiotic exposure, and infant feeding method (breastmilk versus formula).

Breastmilk can be thought of as a microbiome of its own – with more than 600 different types of bacteria as well as a variety of sugars to feed those bacteria.

These sugars, collectively referred to as human milk oligosaccharides (HMOs), are indigestible by the baby, but good bacteria thrive on them. And researchers think this is one way that breastmilk protects baby’s health – the good bacteria can flourish and make it more difficult for the harmful bacteria to cause problems.

Nearly one-third of baby’s gut bacteria are derived from breastmilk, with another one-tenth coming from mother’s areolar skin.

We know that dysbiosis - a disruption in the normal balance of bacteria in the gut - can lead to health issues for children and adults.

Probiotics - microorganisms introduced into the body to promote health - can aid in returning balance to the gastrointestinal system and may heal or prevent issues related to dysbiosis. We are starting to learn that breastmilk acts this way for baby.

Apart from breastfeeding, some parents may wonder if treating baby with additional probiotics might be helpful, or if we can supplement a breastfeeding mom with probiotics to keep her breastfed baby healthy. 

Research into maternal probiotic supplementation shows that by supplementing mom we may be able to decrease the incidence of eczema in babies. 

Rautava and colleagues studied 241mother infant pairs and found that supplementation in the last 2 months of pregnancy as well as the first 2 months postpartum reduced the risk of eczema in babies with a hereditary risk of the skin disorder.

Multiple probiotic strains were used, but all dyads who were supplemented with probiotics fared better than those who took a placebo. Additional research is needed to determine which strains of probiotics are best for the prevention of eczema. 

Mastitis - a painful inflammation and infection of the breast - is typically treated with rest, massage, frequent breast emptying and sometimes antibiotics. Because of the worry about medications transferring to breastmilk, a mother may be concerned about taking prescription medication.

So some researchers are now studying whether the use of probiotics by a breastfeeding mother can prevent or treat mastitis. One study followed three groups of women with mastitis - one supplemented with Lactobacillus fermentum, one supplemented with Lactobacillus salivarius and the third taking an antibiotic - and found that the women taking probiotics had a lower risk of recurrent mastitis.

Flawed methodology, however, make these results suspect. Another study looked at using Lactobacillus salivarus during late pregnancy in women with a history of mastitis with a previous child.

The methodology used in this study was more akin to dairy models than human ones, and the probiotic strain is not available commercially, making the results difficult to generalize to a general population.



 microbiome    microorganisms    breastmilk   probiotics    breastfeeding   lactobacillus    microbiota


The research is, unfortunately, inconclusive when it comes to mastitis; but, probiotics can keep mom’s gut healthy, which in turn will keep her feeling good and may promote beneficial bacteria in breastmilk.

This is especially true if mom is being treated with antibiotics for mastitis. The more we learn about the human microbiota, the better we will understand the way in which we might influence the good bacteria for better health.

Flora Bloom, Intimate Rose Women’s Health Probiotic Supplement promotes vaginal, digestive and urinary health and is suitable for pregnant moms. Our combination of pre- and probiotics helps to restore balance and reduce the risk of infection, keeping you feeling your best during your busy days and nights as a new parent.


Amir, L. H., Griffin, L., Cullinane, M., & Garland, S. M. (2016). Probiotics and mastitis: evidence-based marketing?. International breastfeeding journal11(1), 19.

Dotterud, C. K., Avershina, E., Sekelja, M., Simpson, M. R., Rudi, K., Storrø, O., ... & Øien, T. (2015). Does maternal perinatal probiotic supplementation alter the intestinal microbiota of mother and child?. Journal of pediatric gastroenterology and nutrition61(2), 200-207.

Hunt, K. M., Foster, J. A., Forney, L. J., Schütte, U. M., Beck, D. L., Abdo, Z., ... & McGuire, M. A. (2011). Characterization of the diversity and temporal stability of bacterial communities in human milk. PloS one6(6), e21313.

McGuire, M. K., & McGuire, M. A. (2015). Human milk: mother nature’s prototypical probiotic food?. Advances in Nutrition: An International Review Journal6(1), 112-123.

Mueller, N. T., Bakacs, E., Combellick, J., Grigoryan, Z., & Dominguez-Bello, M. G. (2015). The infant microbiome development: mom matters. Trends in molecular medicine21(2), 109-117.

Pannaraj, P. S., Li, F., Cerini, C., Bender, J. M., Yang, S., Rollie, A., ... & Bailey, A. (2017). Association Between Breast Milk Bacterial Communities and Establishment and Development of the Infant Gut Microbiome. JAMA pediatrics.

Rautava, S., Kainonen, E., Salminen, S., & Isolauri, E. (2012). Maternal probiotic supplementation during pregnancy and breast-feeding reduces the risk of eczema in the infant. Journal of Allergy and Clinical Immunology130(6), 1355-1360.

Tomayko, E., Pillsbury, L., & Pray, L. (Eds.). (2013). The human microbiome, diet, and health: workshop summary. National Academies Press.

Yamada, C., Gotoh, A., Sakanaka, M., Hattie, M., Stubbs, K. A., Katayama-Ikegami, A., ... & Okuda, S. (2017). Molecular insight into evolution of symbiosis between breast-fed infants and a member of the human gut microbiome Bifidobacterium longum. Cell Chemical Biology24(4), 515-524.


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By Dr. Amanda Olson, DPT, PRPC
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