Fertility The Science of Nutrition

How Supporting Your Gut Health Can Improve Fertility

Hillary Bennetts

How Supporting Your Gut Health Can Improve Fertility

Table of contents

  • Intro
  • Why It's Important
  • How You Can Prepare Your Microbiome
  • Stay Curious and Be Empowered

0 min read


The microbiome is the collection of bacteria that live within and on our bodies. While this balance of bacteria is often thought to reside only within the gut, or large intestine, the reality is that your microbiome extends far beyond the digestive tract and throughout your body, colonizing everything from your skin to your reproductive organs. 

In fact, just recently, the Human Microbiome Project determined that the vaginal microbiota accounts for about 9% of the entire female human microbiota. This is significant, especially if you’re planning to become (or already are) pregnant!

Why it's important

We know a healthy microbiome is important in pregnancy, but it’s importance to reproductive health starts long before sperm meets egg. While we previously thought that the vagina alone was populated with bacteria, we now know that most components of both male and female reproductive anatomy, from the ovaries and endometrium (the uterine lining that thickens in preparation for implantation of an embryo) to sperm and follicular fluid, are populated with bacteria. A healthy balance of bacteria in each of these individual microbiomes can impact fertility.

The precise implications of, and means by which the microbiome impacts fertility is still being actively studied. While much of the research around fertility has been done on IVF outcomes as they are more easily controlled in order to draw conclusions, the findings are relevant to anyone trying to conceive. Here’s what we know now about this relationship: 

    • Bacteria in the endometrium: Dysbiotic bacteria in the endometrium was found to be correlated with implantation failure. One study demonstrated this occurrence in IVF patients. It tested endometrial bacteria levels and found that imbalance of the endometrial microbiota was associated with poor reproductive outcomes as compared to IVF patients with a healthier, more balanced bacterial environment in the endometrium. Specifically, more Lactobacillus strains have been associated with better outcomes possibly through modulating the inflammatory and immune response in the endometrium
    • Bacteria in the uterus: Several studies have reported a relationship between the presence of specific bacteria in the uterus and the onset of pelvic inflammatory disease, an inflammation of the upper genital tract that can  impair embryo implantation and the beginning of a successful pregnancy. In other words, a healthy balance of bacteria in the uterus is important to preventing disease and fostering an environment that allows an embryo to implant and result in a viable pregnancy.
    • Bacteria in the vagina: One study analyzing the vaginal microbiota of 130 IVF patients, found that only a small percentage (9%) of those with a vaginal dysbiosis were able to achieve pregnancy, suggesting that vaginal dysbiosis can impact fertility and may negatively impact IVF pregnancy rates 
    • Bacterial changes: It’s also important to note that the vaginal microbiome changes in composition throughout pregnancy and during delivery to protect baby, even if birth is by cesarean section. It is subject to changes in composition of bacteria and pH, as well as infections like bacterial vaginosis. It can take up to a year—for the vaginal microbiome to go back to how it was before pregnancy, so even if conception happened naturally and quickly in a prior pregnancy, microbiome health can be a contributor to secondary infertility. We recommend continuing probiotic supplementation even after delivery while this shift takes place. 

How you can prepare your microbiome 

  • Eat a nutrient-dense diet

  • A diverse diet full of healthy, whole and fermented foods will support the body as a whole, including the microbiome. In addition, what you don’t eat can impact the health of the microbiome as much as what you do. Limiting sugar, alcohol, refined carbohydrates, and caffeine can also support the microbiome by not feeding bad bacteria or contributing to inflammation.

  • Take a targeted probiotic 

  • Since not all probiotic strains can be obtained through food, adding a targeted probiotic can help round out your diet. Lactobacillus has been identified as the most abundant species throughout all of the female reproductive system. These bacteria contribute to the maintenance of a healthy microbiome, and their alterations have been associated with several gynecological diseases that can lead to infertility. Our Pre/Probiotic has 3 targeted Lactobacillus strains that have been specifically studied to support the health of the vaginal microbiome: Lactobacillus rhamnosus HN001, Lactobacillus acidophilus La-14, and Lactobacillus reuteri 1E1. These strains help to convert sugars into lactic acid which increases the acidity of the gut and vagina to help reduce the growth of unfriendly bacteria. 

  • Feed the good bugs

  • The good bugs in your microbiome need fuel to stay populated and require prebiotic “food” to do this. You can support this by consuming plenty of fiber (40-60g/day) and by pairing your probiotic with a prebiotic. Our Pre/Probiotic has two Prebiotics: 

      • MicrobiomeX® is a natural citrus extract rich in polyphenols that supports digestive health and immunity by increasing microbial diversity in the gut and improving gut barrier function. It also helps to reduce inflammation and modulate damaging substances like lipopolysaccharides (LPS). A recent study found that women with recurrent pregnancy loss have a higher prevalence of intestinal barrier dysfunction and significantly increased levels of LPS in the bloodstream, so this inclusion is key to supporting healthy gestation.
      • Livaux™ FOS is sourced from New Zealand gold kiwifruit and has the unique ability to support a healthy gut barrier without feeding unwanted harmful bacteria.
  • Consider your oral health

  • It may seem far from your reproductive organs, but the bacteria in your mouth are related to the bacteria in the rest of your body. Avoid stripping your mouth of bacteria by not using alcohol based washes and harsh toothpastes. These can act like antibiotics do to the gut - they don’t discriminate between good and bad bacteria and wipe it all out. An imbalanced oral microbiome can impact dental health, digestion, and the balance of the microbiome throughout the body.

  • Test for infection
  • As infections can be at the root of dysbiosis within the uterus, vagina, and endometrium, it is wise to rule out common infections such as bacterial vaginosis and pelvic inflammatory disease, as these may contribute to infertility.

  • Get your partner on board 

  • While much of the research around microbiome health in pregnancy has been around female reproductive organs, recent research has suggested that the sperm microbiota can have an impact on characteristics of semen that impact fertility. Specifically, the study found that an abundance of Prevotella (which can be detrimental in large amounts) was found in samples with defective sperm motility while high levels of Lactobacillus strains were found in samples with normal sperm morphology.

    In addition, preliminary research has suggested that the reproductive systems of both partners work in a coordinate manner, something referred to as the “seminovaginal” microbiome. Research suggests that this combined functional unit may influence not only a couples’ reproductive outcomes but also their offspring’s health. More research is needed on this concept, but the overall message is clear: a man’s microbiome matters too when it comes to reproduction and a healthy pregnancy. In addition, preliminary research suggests that as with women, sufficient levels of Lactobacillus species are supportive in the sperm microbiome.

  • Balance your hormones

  • Since optimal gut health requires balanced hormones, make sure you are supporting hormone health with a complete vitamin like our Prenatal Multi and plenty of high quality protein and healthy fats. 

    Stay curious and be empowered

    While there is still a lot to learn about how the microbiome impacts fertility, we know enough to know that it matters. We hope this overview of the reproductive microbiome along with some actionable tips helps you feel empowered to optimize the health of your microbiome for your own fertility and pregnancy journey.

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    Hillary Bennetts, Nutritionist

    Hillary Bennetts is a nutritionist and business consultant focusing on prenatal and postpartum health. In addition to nutrition consulting, she provides business consulting and content creation for companies in the health and wellness industry. Hillary spent almost a decade in corporate consulting before shifting gears to combine her lifelong passion for health and wellness with her business background and nutrition education.