Fertility: It starts in your gut

When we eat foods that we have developed a sensitivity to, it damages the lining of our gut. Often times food sensitivities are developed from eating the same foods over time, which can weaken the lining of our gut, allowing bacteria and other harmful substances to pass from our intestines into our bloodstream, affecting many other organs. 


Our gut health is one of the many factors that can contribute to optimizing our fertility health. The gut microbiome is an ecological community that possesses the most diverse and abundant organisms in the body, with a massive number of bacteria residing in our gastrointestinal tract, providing a broad range of functions. Most of all, the bacterium in our gut helps us digest our food, synthesize nutrients, break down toxins, improve immune function, protect us from harmful micro-organisms, and potentially put us on the path to pregnancy. 


Inflammation can be the cause of many chronic health conditions and unfortunately, that also includes infertility. If the healthy bacteria or processes in the gut are compromised or overwhelmed with harmful bacteria, this can lead to a microbial imbalance. Increased intestinal permeability has been found to play a key role in the development of various inflammatory and autoimmune disorders. Immune disorders are also implicated in reproductive failure, and the seroprevalence of certain autoantibodies such as anti-nuclear antibodies, anti-TPO, antithyroglobulin antibodies, and anti-phospholipids in unexplained infertile women was reported to be higher than in fertile women. Since the microbiome composition affects the repertoire of immunological cells in the mucosa, and dysbiosis is associated with inflammatory diseases, the pathogenesis of infertility might be associated with abnormal immunological responses due to alterations in the microbiota. In this sense, it is plausible that microbiota can play a role in the development of infertility by affecting the epigenetic, immunologic, and/or biochemical functions of the host. PMID: 33960055


Currently, there is growing evidence demonstrating the impact of human microbiota as a factor of health and disease. The microbiota is a group of microorganisms found in mucosal tissues such as the gut, reproductive tract, and skin, which are beneficial for the normal physiology of the host. The human microbiota plays a critical role in multiple biological processes such as nutrient and drug metabolism, maintenance of the structural integrity of the mucosal barrier, immunomodulation, and protection against pathogens. Disruption of the microbiota composition, which results from a decrease in the ratio of beneficial/harmful bacteria, is defined as “dysbiosis.” PMID: 33960055

Dysbiosis can be categorized into three different types: PMID: 33960055

  • loss of beneficial organisms,
  • excessive growth of potentially harmful organisms,
  • and loss of overall microbial diversity.

The microbiota of the female reproductive tract is receiving increasing attention in human reproduction because it may not only impact the chances of achieving a pregnancy, but also the health status of the mother and the child before and after delivery. PMID: 33960055

The vaginal microbiota is most often dominated by Lactobacillus species. However, in some women, it lacks Lactobacillus spp. and is composed of a wide array of strict and facultative anaerobes, a state that broadly correlates with increased risk for infection, disease, and poor reproductive and obstetric outcomes. Interestingly, the level of protection against infection can also vary by species and strains of Lactobacillus, and some species that dominate the vagina microbiome are not always optimal. Recent studies have demonstrated that the relative abundance of L. iners, L. crispatus, and L. gasseri in the vagina can distinguish idiopathic infertile women from fertile women. PMID: 33960055

  • Intestinal permeability is also called "leaky gut" and it can be so detrimental to our health, affecting our vaginal microbiota and fertility.
  • Some common sensitivities include gluten and dairy, but anything your body struggles to digest can increase intestinal permeability and cause a leaky gut. Not getting enough variety in your diet can also cause sensitivities to develop which can lead to a leaky gut.
  • Healing the gut is very important to your fertility, because an imbalanced gut microbiome can cause inflammation and disrupt many different hormonal functions essential to fertility. Studies show that a leaky gut, where the endotoxins leave the gut into the body's circulation negatively impacted the luteal phase. It can lead to lower levels of progesterone and higher levels of ovarian inflammation measured by IL-6. (PMID: 25539190)
  • In women with RLP or Recurrent Pregnancy Loss, leaky gut might occur and allow passage into circulation of immune triggers, potentially able to elicit endometrial innate immune response and, thus, to contribute to miscarriage pathogenesis. Diagnosis and treatment of intestinal disorders underlying leaky gut might improve endometrial environment and pregnancy outcome. PMID: 29665864
  • One of the principal regulators of circulating estrogens is the gut microbiome. The gut microbiota regulates estrogens through secretion of β-glucuronidase, an enzyme that deconjugates estrogens into their active forms. When this process is impaired through dysbiosis of gut microbiota, characterized by lower microbial diversity, the decrease in deconjugation results in a reduction of circulating estrogens. The alteration in circulating estrogens may contribute to the development of conditions discussed herein: obesity, metabolic syndrome, cancer, endometrial hyperplasia, endometriosis, polycystic ovary syndrome, fertility, cardiovascular disease (CVD), and cognitive function. PMID: 28778332
  • A present study linked alterations in the gut microbiota to testicular dysfunction through disruption of polyamine metabolism. The diversity and dynamics of the gut microbiota may be considered as a therapeutic option to prevent male infertility. PMID: 34758869


What are some signs that leaky gut could be contributing to your fertility?

  1. Short Luteal phase

  2. Recurrent pregnancy loss/miscarriage

  3. Implantation failure even though you seem to have good-quality embryos

  4. Has abdominal bloating or frequent gas
  5. Regular heartburn or belching
  6. Frequent diarrhea and constipation, or both
  7. Feel nauseous or vomits regularly
  8. Stools are messy or greasy

A ninja trick to noticing possible gut inflammation that may be affecting your ovaries, is seeing if your post-luteal temps look like a jagged line rather than a straight line. If so, usually this is directly reflective of poor egg quality as a result of sub optimal gut health. 


How can we take care of our Gut?

  • Probiotics. The presence of microbial communities in the reproductive tract has been revealed, and this resident microbiota is involved in the maintenance of health. Intentional modulation via probiotics has been proposed as a possible strategy to enhance reproductive health and reduce the risk of diseases. Probiotics have been reported to play a role in male fertility and affect the health of mothers and offspring. While the female reproductive microbiota is more complicated and has been identified in both the upper and lower reproductive systems, they together contribute to health maintenance. Probiotics have shown regulatory effects on the female reproductive tract, thereby contributing to homeostasis of the tract and influencing the health of offspring. Further, through the transmission of bacteria or through other indirect mechanisms, the parent's reproductive microbiota and probiotic intervention influence infant gut colonization and immunity development, with potential health consequences. PMID: 35465162
  • Prebiotics. These are the foods, like plant fibers, that feed the good bacteria in our gut to give it the advantages in the fight. So, eat your veggies!
  • Reduce processed sugar and inflammatory seed oils.  It will invigorate the growth of the wrong kind of gut bacteria, and it will trigger the release of harsh dietary emulsifiers that will cause inflammation in our gut. 

In my practice, one of the tests I recommended is a whole-blood Food Sensitivity test (not IgG/IgA, which are more common but less accurate)--- there are many on the market, so please don't be fooled. We have found it more accurate to do whole blood testing for assessing food sensitivities, and in turn intestinal permeability. It allows me to see if there are any foods that may be contributing to inflammation in the gut, because inflammation often leads to infertility. Moreover, it helps us assess and create a plan for intestinal healing that will support your fertility conception AND the ability to carry to term. For couples who are on a #ttc journey or trying to conceive, your gut microbiome is one of the core areas to start with when it comes to optimizing fertility health!