The Connection Between the Vaginal Microbiome and Fertility
When we think about fertility, we often focus on ovulation, hormone levels, and overall reproductive health. However, there’s a crucial yet often overlooked factor—the vaginal microbiome. This delicate ecosystem of bacteria and microorganisms plays a vital role in maintaining reproductive health, protecting against infections, and even supporting conception.
A well-balanced vaginal microbiome, primarily dominated by Lactobacillus species, ensures an optimal pH level, providing a protective environment for sperm and reducing inflammation that could hinder pregnancy. When the balance is disrupted—due to stress, medications, toxins, diet, antibiotics, or infections—it can lead to conditions like bacterial vaginosis (BV), which may negatively impact fertility.
The Role of Lactobacillus in Fertility and Reproductive Health
A healthy vaginal microbiome is primarily dominated by beneficial Lactobacillus species. These bacteria help maintain the vaginal pH, creating an environment conducive to sperm survival and reducing the risk of inflammation that can make conception more difficult. A low Lactobacillus count can disrupt this balance, leading to an overgrowth of harmful bacteria like Gardnerella vaginalis and Ureaplasma, increasing the risk of infections that may impair fertility.
Factors That Disrupt Vaginal Microbiome Balance and Fertility
Stress, medications, toxins/chemicals in our environment (Eg. artificial fragrances and synthetic materials found in our clothing and undergarments), diet, antibiotics, and bacterial infections can disrupt the vaginal microbiome balance, leading to a range of fertility challenges. Some women struggle with recurrent infections, unexplained infertility, or failed IVF cycles, and in many cases a disrupted microbiome is a contributing factor. Testing often reveals low Lactobacillus levels and an overgrowth of harmful bacteria. Restoring a healthy Lactobacillus dominated microbiome may improve reproductive outcomes by creating a balanced vaginal microbiome, reducing inflammation, and preventing overgrowth of harmful bacteria that could contribute issues with reproductive health.
Research on the Vaginal Microbiome and Fertility
Several studies have shown the importance of Lactobacillus in fertility:
- Association with Infertility: Research suggests a negative correlation between low Lactobacillus species and infertility, highlighting that a healthy vaginal microbiota can reduce the chances of infertility.
- Impact on Embryo Implantation: Studies indicate that low Lactobacillus levels in the uterus are linked to decreased implantation success during assisted reproductive treatments like IVF.
- Negative Pregnancy Outcomes: Reduced Lactobacillus levels and increased microbial diversity are consistently associated with poor pregnancy outcomes, including miscarriage, pre-term labour and infertility.
Vaginal Infections and Their Impact on Fertility
Vaginal infections like Ureaplasma and bacterial vaginosis (BV) can interfere with conception, implantation, and pregnancy outcomes. Let’s explore the role of these infections in fertility:
- Ureaplasma and Fertility
Ureaplasma species are part of the normal genital flora but can cause fertility issues when overgrown. Research links Ureaplasma infections to:
- Infertility: Increased inflammation in the reproductive tract can impair sperm function and embryo implantation.
- Pelvic Inflammatory Disease: Chronic infections can lead to PID, damaging the fallopian tubes and increasing the risk of ectopic pregnancy.
- Pregnancy Complications: Ureaplasma infections have been associated with miscarriage and preterm labour.
- Bacterial Vaginosis (BV) and Fertility
BV occurs when there is an imbalance in the vaginal microbiome, with a decrease in Lactobacillus and an overgrowth of harmful bacteria like Gardnerella vaginalis. BV is a vaginal infection, characterized by fishy smelling vaginal discharge with a grayish hue. Studies suggest:
- Lower Conception Rates: BV is linked to lower pregnancy rates in natural conception due to an altered vaginal pH, which can impair sperm function.
- Increased Risk of Miscarriage: Untreated BV in early pregnancy is associated with a higher risk of first-trimester miscarriage.
- Complications in Assisted Reproduction: BV may affect embryo implantation success and IVF outcomes due to inflammation and changes in the uterine lining.
Vaginal Infections and Their Impact on Uterine Health and Fertility
This area is still under discussion, but some studies suggest that bacteria from the vagina can ascend into the uterus, leading to infections. This is especially relevant in conditions such as bacterial vaginosis, pelvic inflammatory disease, and complications following childbirth or surgery. Uterine infections can interfere with embryo implantation and increase the risk of pregnancy complications, including pre-term birth. Nowadays, it’s becoming more common for specialists to perform a uterine biopsy to test for infections before embryo transfer. Some IVF clinics use tests called EMMA (Endometrial Microbiome Metagenomic Analysis) and ALICE (Analysis of Infectious Chronic Endometritis) to test for uterine infections and evaluate the balance between beneficial and harmful bacteria before an embryo transfer. Studies suggest:
- Ascending Infections: Vaginal bacteria such as Gardnerella vaginalis, Mycoplasma hominis, and Ureaplasma urealyticum can travel to the uterus and fallopian tubes, contributing to infections. PID-causing STI’s like gonorrhoeae and chlamydia can also spread to the reproductive organs and lead to conditions like Hydrosalpinx, a blockage of the fallopian tubes that can be a sequel to pelvic infections.
- BV and Uterine Infections: BV increases the risk of endometritis and pregnancy complications, with studies detecting BV-related bacteria in the endometrium.
- Postpartum & Post-Surgical Infections: Childbirth, caesarean sections, IUD placement, or procedures like D&C can allow vaginal bacteria to enter the uterus, raising infection risks.
- Menstrual Cycle Influence: Bacterial movement may be aided by cervical changes and uterine contractions during menstruation.
Supporting Vaginal Health for Better Fertility
To optimize fertility, restoring a balanced vaginal microbiome is essential. Here are natural ways to support vaginal health and fertility:
- Probiotics: Probiotics containing specific Lactobacillus strains like Lactobacillus crispatus, Lactobacillus reuteri, and Lactobacillus rhamnosus may help restore a healthy vaginal environment by promoting beneficial bacteria and maintaining optimal pH levels.
- Herbal Remedies: Herbal medicine may support inflammation reduction, blood flow, and gut health, all of which play a role in maintaining a healthy microbiome.
- Antibiotics: While antibiotics may be helpful for persistent infections, they can disrupt the delicate vaginal microbiome. Following antibiotic treatment with probiotics and herbal support can help restore balance and prevent recurrent infections.
- Diet: Eating a whole food diet is always best. Avoiding processed food items, sugar and alcohol will help to keep vaginal environment balanced. Be aware of any food intolerances or allergies that may contribute to inflammation.
- Lifestyle: Adequate rest, exercise and nervous system support is essential for the health of the vaginal microbiome. The vaginal environment can be affected by prolonged high stress and improper sleeping/eating habits. Activities like smoking, vaping and illicit drug use can contribute to imbalances in the vaginal microbiome.
Prioritize Your Vaginal Microbiome for Fertility Success
Studies suggest that maintaining a balanced microbiome can enhance fertility and reproductive success. By addressing microbiome imbalances with probiotics, lifestyle changes, herbal remedies, and medical treatments when necessary, you can optimize your chances of conception and support long-term reproductive health.
It’s becoming increasingly common for gynaecologists and fertility specialists to prescribe probiotics to support the uterine and vaginal microbiomes in their patients, especially after the diagnosis of a uterine infection and a course of antibiotics. As the significance of this area in fertility outcomes becomes more recognized, prioritizing vaginal health during your conception journey is highly beneficial.
Improve Your Vaginal Health Today
Focusing on your vaginal microbiome as part of your preconception and fertility journey is essential for optimizing fertility. The best place to start is by finding a knowledgeable practitioner who can order a comprehensive vaginal microbiome panel. Ideally, this should be done 3–6 months before trying to conceive, but it remains valuable even if you’re currently undergoing IVF.
Vaginal health is a crucial yet often overlooked aspect of fertility preparation, and it’s something I’m deeply passionate about. If you’re struggling with fertility and unsure where to begin, reach out to schedule an appointment—we can start the investigative process together.
Sources:
Nedjoua Sekhri-Arafa1 et al. (2024) Prevalence of Ureaplasma urealyticum in infertile women and its impact on reproduction. Retrieved from https://publishing.emanresearch.org
Kletzel, H.H., Rotem, R., Barg, M. et al (2018). The pathogenic role of Ureaplasma urealyticum in gynecological and obstetric conditions. Current Infectious Disease Reports. Retrieved from https://link.springer.com
Ravel, Jacques et al. (2021). Bacterial vaginosis, infertility, and endometritis: Disruptions in vaginal flora as a contributing factor. American Journal of Obstetrics and Gynecology. Retrieved from https://ajog.org
Haggerty, C. L., et al. (2004). Lower genital tract infection and endometritis: Insights into subclinical PID. Clinical Infectious Diseases, 39(7), 990-995. https://doi.org/10.1086/423185
Wiesenfeld, H. C., et al. (2021). Pelvic inflammatory disease: New diagnostic criteria and treatment. American Journal of Obstetrics and Gynecology, 224(3), 222-231. https://doi.org/10.1016/j.ajog.2020.08.037
Hillier, S. L., et al. (1995). Bacterial vaginosis and the risk of upper genital tract infection. American Journal of Obstetrics and Gynecology, 172(5), 1426-1431. https://doi.org/10.1016/0002-9378(95)90405-7
Committee on Practice Bulletins—Gynecology. (2015). Pelvic inflammatory disease. Obstetrics & Gynecology, 126(6), e85-e102. https://doi.org/10.1097/AOG.0000000000001150
Katherine T Chen. (2025). Postpartum endometritis. Retrieved from https://www.uptodate.com/contents/postpartum-endometritis
