Everything You Needed to Know About the Vaginal Microbiome

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January 22, 2018
vaginal microbiome, female naturopathic doctor, toronto naturopath

The vaginal microbiome plays an important role in women’s health. A healthy microbiome is generally described as a lack of symptoms and unwanted chronic infections.

Establishing the Vaginal Microbiome

The microbiome development closely follows the onset of menstruation. Before a girl gets her first period, the vaginal microbiome is composed of a mix of skin and gut microbes with few Lactobacillus strains. Once she has reached puberty, Lactobacillus growth occurs because of favourable conditions (ie. estrogen and progesterone production). Estrogen supports vaginal tissue growth and glycogen. Whereas, progesterone supports the breakdown of tissue cells leading to the release of glycogen. 

Because of the decrease of estrogen during menopause, the Lactobacilli population may decrease – thus reducing the amount of lactic acid produced and shifting the vaginal pH. 

How Lactobacilli Work

In short, when Lactobacilli eat glycogen, the end result is the production of lactic acid. The lactic acid results in a lower pH of 3.8-4.4, creating an acidic environment that is unfavourable for the growth of pathogenic bacteria (ie. Gardnerella and E.coli). 

Vaginal Microbiome Diversity in Women

Unlike the gastrointestinal tract, the bacterial diversity in the reproductive tract is quite narrow and Lactobacillus is the predominant species. Nevertheless, not all women have the same vaginal mirobiome. Species range among different ethnicities. There are 5 grades to the vaginal microbiome. Grades 1, 2, 3 and 5 are dominated by the Lactobacillus strains and are seen in a majority of White and Asian women. While Grade 4 is common in Black and Hispanic women and is primarily composed of non-Lactobacillus strains (ie. Gardnerella is one of the primary strains). 

What Influences the Vaginal Microbiome?

Briefly, some of the factors that affect the microbiome are: age, pregnancy, smoking, sexual activity and external hormones. 

IVF Transfer

According to a 2017 paper, successful embryo transfer is dependent on many factors including the microbiome! The uterocervical microbial colonization can influence conception rates. The role of the microbiome in reproduction is still quite new, so further research is required. 


While this isn’t a popular form of birth control, using a cervical cap and/or spermicide can actually increase E.coli and other non-Lactobacillus species. 

The birth control pill and other contraceptive devices may also influence the microbiome.

Endometriosis Treatments

For women living with endometriosis and taking GnRH agonists like Lupron, the vaginal pH may slightly increase (becoming less acidic) after 4-6 months of treatment. One study showed a higher colonization of Gardnerella and E. coli in these women. 


When you take something to wipe out ‘bad’ bacteria, you’re also wiping away good bacteria. Probiotic supplements can be taken alongside antibiotic treatment, however should be space apart and the type is dependent on your specific conditions and symptoms. Visit your ND for more information.  

Final Thoughts

Whether you are living with chronic vaginal infections or pregnant and don’t want to be GBS+, it’s clear that the vaginal microbiome plays a big role in how you’re doing. Luckily it can be modified, even if it does take some time. Visit the links above to learn about what to look for in a probiotic.  

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