While the causes of infertility are linked to male, female, or combined factors in 75% of cases, between 10% and 25% remain unexplained. This is why an increasing number of studies are exploring the role of the genital microbiome in fertility.
For couples who do not use contraception, the chance of conception in a single menstrual cycle is between 20% and 25%. When pregnancy does not occur after 12 months of regular unprotected intercourse, infertility is diagnosed. This issue affects between 18% and 24% of couples in France today – approximately one in five couples.
According to the French Biomedicine Agency, 157,593 in vitro fertilization (IVF) attempts were performed in France in 2019, representing a 5% increase compared to 2016. As a result, 27,063 babies were born, and the birth rate from IVF rose to 3.6% in 2019 (compared to 2.6% in 2009).
It is well known that vaginal dysbiosis (an imbalance in the microbiome) can increase the risk of infertility, but the role of the uterine (endometrial) and seminal microbiome is only beginning to be explored.
Could the balance of microorganisms in reproductive organs be a key factor for successful conception?
How can we improve microbiome health and increase the chances of pregnancy?
Does the Genital Tract Microbiome Influence Fertility?
Infertility is a growing health challenge, and one of the often-overlooked causes is the microbiome of the genital tract. Research suggests that bacterial imbalances, known as dysbiosis, may contribute to reduced fertility in both women and men by increasing the risk of infections and inflammatory processes in reproductive organs.
The Female Genital Microbiome and Infertility
In women, abnormalities in the fallopian tubes (inflammation, damage to ciliated cells, blockages) account for 14–20% of infertility cases. Additionally, chronic inflammation of the endometrium (endometritis) is present in 12–46% of women experiencing infertility. In 85% of cases, these lesions result from sexually transmitted infections (STIs), with Chlamydia trachomatis, Neisseria gonorrhoeae, and Mycoplasma genitalium being the most common culprits.
However, it is important to emphasize that vaginal dysbiosis increases the risk of these infections. Studies have shown that a decrease in lactobacilli in the vagina increases the prevalence of HPV and Chlamydia trachomatis infections, while other bacteria associated with bacterial vaginosis can directly contribute to infertility. Recent research has linked Atopobium vaginae, Sneathia sanguinegens, Megasphaera, and Prevotella amnii to upper genital tract infections.
Thanks to advanced sequencing techniques, it has been discovered that bacteria can migrate from the vagina to the uterus, causing inflammation and disrupting conditions for embryo implantation. These findings are crucial for the development of new therapeutic approaches, as many "new" bacteria are resistant to standard antibiotics, while the use of lactobacilli in prevention is gaining importance.
The Seminal Microbiome and Male Fertility
Male factor infertility is present in up to 50% of cases, either alone or in combination with female factors. The causes are diverse—smoking, alcohol, aging, genetic factors, hormonal imbalances, infections, and inflammatory conditions such as prostatitis and epididymitis.
Although semen was long thought to be sterile, we now know it contains a specific microbiome. The presence of certain bacteria can affect sperm function by reducing motility, causing agglutination, or even inducing apoptosis (programmed cell death). Some studies suggest that the presence of lactobacilli may be beneficial, but that certain species, such as Lactobacillus iners, may negatively impact sperm quality.
Interestingly, sexual partners exchange microbiomes during intercourse. For example, the presence of Gardnerella vaginalis in women with bacterial vaginosis has been linked to inflammation in the male urogenital tract. Research also suggests that the microbiome of the penile skin and urethra in men can vary depending on the vaginal microbiome of their partners.
Conclusion
Understanding the impact of the microbiome on fertility opens the door to new therapeutic strategies. While antibiotics remain the primary treatment for infections, growing evidence suggests that balancing the microbiome through probiotics could play a vital role in maintaining reproductive health. Further research will help define more precise methods for preventing and treating infertility caused by microbiological factors.
Source:
Jean-Marc Bohbot. The genital microbiotas’ impact on fertility. La revuedes Microbiotes. MARCH 2022. Issue 22. Avaiable at: https://www.larevuedesmicrobiotes.com/issues/mycobiota-bacterial-fungal-interactions-within-microbiota#vignette?utm_source=Sarbacane&utm_medium=email&utm_campaign=2025-02-26-LRDM-30-EN
For this reason, the HEALTH FORMULA protocol places special emphasis on maintaining eubiosis through proper nutrition, supplementation and other healthy live-stile. Maintaining microbiome balance, positively impacts not only overall health but also reproductive function, providing natural support for fertility.
