How Do Probiotics Help Fertility

Jul 15, 2020 11:52:03 AM

Written By:
Ramneek S. Bhogal, DC, DABCI


Understanding how the benefits of probiotics extend beyond the gut and help with fertility is a big leap for some people.*

Even though our gut microbiome has many local benefits, a healthy colony of GI flora creates a positive full-body impact. For women, probiotics are especially useful because many of the same species of microflora in our gut are also a natural part of the uterine and vaginal microbiome.*

How does a healthy, thriving gut microbiome directly affect female reproductive organs?



Learn about supplements that play key roles in fertility.* Check out our guide.

Similarities Between the Vaginal and Gut Microbiomes

Although several different microflora species exist in both the vaginal-uterine and GI microbiome, various genera of Lactobacillus and Bifidobacterium are naturally present in a healthy gut and vagina.

As for Bifidobacterium, a study in the late 1990s on 56 healthy women of reproductive age showed that four strains dominated the vaginal colony: B. bifidum, B. breve, B. adolescentis 2, and B. longum.

Just like in the gut, B. bifidum G1 has a hard time adhering to cell walls. But the other three strains of Bifidobacterium showed high capability in vaginal epitheliocyte adhesion. Along with being one of the predominant vaginal and adult GI microflora, Bifidobacterium is also the dominant intestinal bacteria in healthy, breast-fed infants

The second, and perhaps most significant genus of microflora for vaginal health is Lactobacillus.* Lactobacillus exists in the high quantity in the gut as well. In the human GI tract, some of the most common strains are L. rhamnosus GG, L. casei Shirota YIT9029, L. casei DN-114 001, L. johnsonii NCC 533, L. acidophilus LB, and L. reuteri DSM 17938, and L. plantarum.

The most dominant strain in the vagina is Lactobacillus acidophilus. But Lactobacillus crispatus, Lactobacillus gasseri, Lactobacillus iners, and Lactobacillus jensenii, L. plantarum, and L. rhamnosus are all present as well.

So, you can see that there is a lot of cross-over between the two microbiomes.

See more on How probiotics impact women's health: Women's Health supplements & nutrition guide

How Probiotics and the Vaginal Microbiome Impact Fertility

Balance is key, whether speaking of the gut or urogenital microbiome. The most common causes of imbalance include stress, poor diet, environmental toxins, and sub-optimal hydration. Probiotics help keep microflora at healthy levels in light of these common, yet adverse life factors.*

Known areas of fertility impacted by the GI & vaginal microbiomes:


  • The pH Environment — Lactobacillus exudes lactic acid, which helps to keep the vaginal pH slightly acidic.* A well-regulated vaginal pH makes it more difficult for problematic microbes to establish colonies – such as Gardnerella vaginalis. When colonies of common bacteria like G. vaginalis or Preveotella are established, the inflammatory response and immune activity are affected, which can create an inhospitable environment for fertility. On top of this, spermatozoids need an alkaline environment to survive. Because of this, the female body releases cervical mucus during times of ovulation to counteract the necessary acidic environment for brief periods, so pH levels need to be balanced before ovulation for optimal fertility.
  • Sperm Motility — When there is a shift in pH and supportive microflora, it can affect sperm's transition through the vaginal canal. When there aren't enough 'good' bacteria present,the agglutination of spermatocytes is more likely. This means that spermatozoids may bind together and lose motility. Studies also show that men who have replete probiotic levels may have more youthful serum testosterone levels which can translate into better overall sperm quality.[1]*
  • Menstrual Cycles and Endometrium — Research shows a correlation between suboptimal microbiota in women and irregular menstruation. The more regular healthy menstruation and ovulation, the more you are stacking the deck in favor of conception. Lactobacilli also impact the endometrium – which is why we theorize that gut and vaginal microflora may affect the menstrual cycle.*
  • Immune Health — The positive microflora colonies throughout our body act as immune signalers both locally and system-wide. The gut-associated lymphoid tissue is the largest immunological organ in the body, and through the bloodstream, it tells the brain when to upregulate or down-regulate the immune system. It also sends a signal when our microflora is off or GALT regulation is affected. If the body is in a healthy immune and inflammatory state, it stacks the cards in favor of fertility.
  • BMI — Body Mass Index is lower-hanging fruit when it comes to trouble-shooting fertility. A fertility specialist will likely recommend a suggested BMI range for optimal fertility on a person-to-person basis. Probiotics and our gastrointestinal function directly relate because a healthy microbiome helps us achieve better nutrient absorption.* A healthy GI can help with satiety and reduce cravings for excess salt and carbs. There is also a trickle-down effect related to energy. When you utilize nutrients better, you're likely to have more energy, stay active, and feel better.


Probiotics can help with fertility by keeping the gut and vaginal microbiomes at healthy levels.* It's part of a multi-faceted approach to overall health, which acts as an umbrella over various sub-systems that directly relate to fertility – bodyweight & metabolism, a healthy vaginal mucosa, pH & sperm motility, and improved immune and inflammatory response, and regular ovulation. When we add all of these things up, we put the female body in the best possible place for fertilization and pregnancy.


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[1] "Probiotic Microbes Sustain Youthful Serum ... - NCBI - NIH." Accessed 28 Jun. 2020.

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.