Reproductive Microbiomes and Fertility

Why Microbial Health Matters Before Conception and IVF

When people think about preparing for pregnancy, the focus is often on hormones, ovulation, egg quality, sperm health, supplements, and timing.

But there’s another piece of the puzzle that is increasingly gaining attention in reproductive medicine:

The reproductive microbiomes and fertility…

Research continues to demonstrate that microbial environments throughout the reproductive tract may influence conception, implantation, inflammation, IVF outcomes, and pregnancy health.

At Intimate Ecology, we support many individuals and couples navigating fertility journeys, both natural conception and assisted reproductive treatments such as IVF and ICSI, who are seeking a more comprehensive understanding of how microbial health may be influencing their reproductive landscape. And whilst microbiome health is not the only driver of fertility struggles it is a commonly overlooked area which needs our attention.

What is the reproductive microbiome?

The reproductive microbiome refers to the communities of microbes that exist throughout the reproductive tract.

This includes:

• The vaginal microbiome
• The cervical environment
• The endometrial or uterine microbiome
• The seminal microbiome
• Penile and genitourinary microbiomes

In a healthy vaginal state, the microbiome is typically dominated by Lactobacillus species, protective bacteria that help:

• Maintain an acidic vaginal pH
• Reduce inflammation
• Inhibit opportunistic organisms
• Support mucosal and immune integrity

However, these ecosystems are dynamic and influenced by:

• Hormones
• Antibiotic exposure
• Stress
• Sexual activity and semen exposure
• Immune function
• Inflammation
• Infection
• Metabolic and nervous system health

When microbial disruption occurs, we may see patterns associated with:

• Bacterial vaginosis (BV)
• Recurrent thrush
• Urinary symptoms
• HSV recurrence
• Chronic inflammation
• Persistent reproductive tract symptoms

And increasingly, we are seeing evidence that these shifts may also influence fertility and implantation outcomes.

Why reproductive microbiome health matters before conception

The reproductive microbiome is not passive.

These microbial ecosystems interact directly with:

• Cervical mucus
• Immune signaling
• Inflammatory pathways
• Vaginal and endometrial environments
• Sperm survival and motility

A disrupted microbiome may contribute to:

• Increased cervical inflammation
• Altered mucus quality
• Reduced microbial stability
• Greater inflammatory burden within the reproductive tract

Research has associated non-Lactobacillus-dominant microbiomes with:

• Increased time to conception
• Reduced implantation rates
• Lower IVF success rates
• Adverse reproductive outcomes

This does not mean fertility challenges are caused by one specific bacterium.

But it does suggest that the microbial environment may influence how receptive, stable, and inflammatory the reproductive landscape is during conception and implantation.

Fertility is not just vaginal: it’s an ecosystem

One of the biggest shifts occurring in reproductive medicine is the understanding that fertility is deeply interconnected with the broader reproductive microbiome ecosystem.

At Intimate Ecology, this means that when clinically appropriate, we may also assess:

• The seminal microbiome
• Penile/genitourinary microbiome health
• Menstrual blood microbiome patterns as a reflection of the uterine environment

Because conception does not occur in isolation.

The vaginal microbiome interacts dynamically with sperm, seminal fluid, the cervix, the immune system, and the endometrial environment. Emerging evidence suggests microbial balance across these reproductive environments may influence implantation, inflammation, embryo receptivity, and reproductive outcomes.

The seminal microbiome and fertility

Research suggests that the seminal microbiome may influence:

• Sperm quality
• Motility
• DNA fragmentation
• Oxidative stress
• Genitourinary inflammation
• Fertility outcomes

In some couples, recurrent vaginal microbiome disruption may also involve microbial exchange between partners. This is why fertility focused microbiome support sometimes needs to involve both people, not just the person carrying the pregnancy.

This can be particularly relevant in cases involving:

• Recurrent BV
• Persistent vaginal dysbiosis
• Recurrent implantation failure
• Unexplained infertility
• Chronic genitourinary symptoms

What can menstrual blood tell us about the uterine microbiome?

The uterine or endometrial microbiome is one of the most rapidly evolving areas of fertility research.

While direct endometrial biopsy testing exists, it can be invasive, expensive, and impractical for many people.

Emerging microbiome analysis techniques now allow menstrual blood microbiome assessment to be explored as a less invasive reflection of the uterine and endometrial environment.

Whilst this area is still evolving, menstrual blood microbiome patterns may provide insight into:

• Endometrial inflammation
• Implantation-related microbial patterns
• Reproductive tract dysbiosis
• The broader inflammatory environment involved in fertility

Importantly, microbiome findings are never interpreted in isolation. They are considered alongside:

• Symptoms
• Hormonal health
• Fertility history
• Immune and inflammatory patterns
• IVF timelines and treatment stages
• Vaginal microbiome results

Because microbes on a report only become meaningful in the context of the whole person.

Vaginal microbiome health and IVF

One of the areas receiving growing attention in reproductive medicine is the relationship between microbiome composition and assisted reproductive technologies.

Several studies have explored whether a Lactobacillus dominant reproductive environment may be associated with:

• Higher implantation rates
• Improved embryo transfer outcomes
• Greater pregnancy success rates

Interest in microbiome targeted interventions is also growing. A recent systematic review and meta-analysis examining vaginal probiotic use around embryo transfer found a trend toward improved clinical pregnancy outcomes and reduced miscarriage rates, although the findings did not reach statistical significance. Together with growing evidence linking Lactobacillus dominant reproductive microbiomes to improved IVF outcomes, these findings suggest that microbiome support may become an increasingly important component of fertility care as the evidence base continues to evolve.

Whilst this field is still evolving, the emerging evidence is significant enough that many fertility practitioners and patients are now considering microbiome support as part of preconception and IVF planning.

Importantly, microbiome support is not simply about eliminating “bad bacteria.”

It is about:

• Reducing inflammatory burden
• Improving microbial stability
• Supporting mucosal integrity
• Creating a more resilient reproductive environment

Fertility planning is not one size fits all

At Intimate Ecology, fertility microbiome support is always individualised.

Some people present with:

• Recurrent BV or thrush
• Chronic urinary symptoms
• HSV recurrence
• Previous implantation failure
• Recurrent pregnancy loss
• Pelvic inflammation
• Vaginal discomfort despite “normal” testing

Others may simply want to optimise their reproductive environment prior to trying to conceive or beginning IVF.

Support may include:

• Vaginal microbiome testing
• Nutritional and herbal medicine support
• Custom vaginal probiotic or herbal pessaries
• Hormonal and immune support
• Partner microbiome considerations
• Seminal or penile microbiome support where relevant

All recommendations are made in consideration of your fertility timeline and treatment stage.

How long does microbiome restoration take?

This is one of the most important discussions in fertility-focused microbiome care.

Microbiome change takes time.

Whilst symptoms may improve relatively quickly, meaningful shifts within the microbial ecosystem often occur more gradually.

Ideally, we prefer to work with at least three menstrual cycles prior to conception or embryo transfer where possible. The more the better.

However, fertility timelines are not always flexible and we understand that.

Support can still be provided:

• During active conception attempts
• In the lead-up to embryo transfer
• Between fertility treatment cycles
• Alongside existing fertility treatment plans

Sometimes treatment strategies need to be adjusted to fit shorter fertility windows, and these discussions form an important part of clinical planning.

What if you’re already taking fertility supplements?

Many people seeking microbiome support are already on comprehensive fertility protocols.

At Intimate Ecology, treatment is collaborative.

Your practitioner will review:

• Existing supplements
• Hormonal support protocols
• Fertility medications
• Vaginal and microbiome focused treatments

This allows us to ensure your support remains:

• Targeted
• Evidence-informed
• Appropriate for your current fertility phase

Rather than simply adding more supplements unnecessarily.

The emotional side of fertility and vaginal health

Fertility journeys can be deeply emotional, particularly when recurrent symptoms, microbiome imbalances, or unexplained inflammation become part of the picture.

Many people arrive feeling:

• Frustrated
• Dismissed
• Exhausted from recurrent treatments
• Confused by conflicting information online

This is why supportive, nuanced care matters.

At Intimate Ecology, our approach is inclusive, collaborative, and grounded in understanding the complexity of both reproductive and microbiome health. We will suggest psychological fertility care referrals as appropriate.

The goal is not perfection. It’s resilience.

One of the most important things to understand is that vaginal microbiome health is not about achieving a “perfect” microbiome report.

It is about creating:

• Stability
• Reduced inflammation
• Improved resilience
• Better symptom patterns
• A more supportive reproductive environment

Need support with fertility microbiome health?

Intimate Ecology supports individuals and couples through:

• Preconception microbiome restoration
• IVF and embryo transfer preparation
• Recurrent BV and thrush
• Recurrent UTI
• HSV support
• Vaginal and urinary symptoms
• Support in chronic endometritis cases
• Support during and post antibiotic protocols
• Hormonal and immune support
• Partner microbiome considerations
• Holistic fertility support

If you’d like to explore whether vaginal microbiome support may be appropriate for your fertility journey, our fertility focussed clinician Jessie-Anne can guide you through testing, interpretation, and treatment options tailored to your individual needs.

Book a Fertility and Microbiome Couples Consultation with Jessie-Anne BOOK HERE

You may also find these instagram posts relevant.

• Embryo transfer success and cervicovaginal microbiome: View Instagram post here
• Seminal Microbiome and Vaginal Microbiome recovery: View Instagram post here
• Unexplained infertility. The hidden role of chronic endometritis: View Instagram post here
• Can I use intravaginal treatment while trying to conceive? View Instagram post here
• Vaginal Microbiome and Miscarriage risk: View Instagram post here
• Do I need to treat asymptomatic BV if I am considering pregnancy? View Instagram post here
• High Gardnerella in the uterine microbiome- do I need to treat? View Instagram post here
• Endometrial and vaginal microbiome relationships: View Instagram post here

Practitioner looking for education in this area?

Check out these courses from Dr Moira Bradfield Strydom.

• Pregnancy and the Vaginal Microbiome HERE
• The Endometrial Microbiome HERE
• The Penile and Seminal Microbiome 2024 HERE
• The BV Big 5 HERE
• Now enrolling for 6 month mentoring: Vagiversity August 2026 HERE

 

References

Li, L., Feng, L., Li, Q., Zhou, Y., Liu, S., Song, H., … & Liu, S. (2026). Precision Microbial Therapeutics for Infertility: Next‐Generation Probiotics, Engineered Biologics and Translational Pathways. Microbial Biotechnology, 19(3), e70330

Maleki-Hajiagha A, Karimi R, Abbasi S, et al. Vaginal probiotics as therapeutic adjuncts for improving embryo transfer success rates: a systematic review and meta-analysis. BMC Pregnancy and Childbirth. 2025;25:262.

Moreno I, et al. Evidence that the endometrial microbiota has an effect on implantation success or failure. American Journal of Obstetrics and Gynecology. 2016;215(6):684–703.

Haahr T, et al. Abnormal vaginal microbiota may be associated with poor reproductive outcomes: a prospective study in IVF patients. Human Reproduction. 2016;31(4):795–803.

Koedooder R, et al. The vaginal microbiome as a predictor for outcome of in vitro fertilization with or without intracytoplasmic sperm injection: a prospective study. Human Reproduction. 2019;34(6):1042–1054.

Vollmer Mackenzie T, et al. The vaginal microbiome and assisted reproductive outcomes. Fertility and Sterility.2024;121(2):233–242.

Singer M, et al. Vaginal microbiota and fertility: a review of the current evidence. Fertility and Sterility.2023;119(5):761–772.