The Uterine Microbiome and Recurrent Pregnancy Loss

A new way to look at miscarriage risk and what you can do next...

If you have experienced a loss or you are preparing for IVF, this is for you. A brand new study suggests that it is not only which bacteria live in the uterus that matters, but how well those bacteria work together as a community. This is a fresh angle that very few people hear about in regular fertility visits, and it may help explain why some pregnancies struggle to continue even when all the usual tests look normal.

In simple terms:

• A healthy uterine lining is usually rich in Lactobacillus, a friendly group of bacteria that help keep the environment calm and protective.

• In people with recurrent pregnancy loss, the study found less Lactobacillus and more potentially unhelpful bacteria like Gardnerella, Streptococcus, and Staphylococcus.

• There was also more total bacterial load and a different overall mix of microbes compared with controls.

• Here is the novel piece. The authors mapped how uterine microbes connect with one another and found that in recurrent loss the microbial network is fragile. Think of it as a web with fewer strong strands. It is easier to disrupt and harder to bounce back.

  
  

Why a fragile network could matter

Microbes do not live alone. They cooperate and compete. A resilient community helps the lining regulate inflammation, manage invaders, and support implantation. When the network is fragile, small shifts can tip the balance toward inflammation and instability, which may make it harder to sustain an early pregnancy.

A quick look at what the researchers did:

• They analyzed uterine lining samples from people with and without recurrent loss.

• They measured which bacteria were present and how abundant they were.

• They used modern analytics, including machine learning, to flag genera linked with loss. Streptococcus and Chryseobacterium came up as risk signals, while Fusobacterium showed a different pattern that needs more study.

• They built microbe to microbe network maps and tested how easily the network would break when key nodes were removed. The recurrent loss network broke more easily.

  
  

What this could mean for you:

This work supports something many of us see in practice. Uterine health is about balance and cooperation, not only the presence or absence of a single bug. That opens several practical paths:

• Targeted testing: When history suggests a role for inflammation or infection, assessment of the uterine microbiome could be considered. Testing is not for everyone, but for the right case it can be clarifying.

• Personalized support: Care plans can include evidence based antimicrobial or anti inflammatory strategies when indicated, nutrition plans that support microbial balance, and steps that restore Lactobacillus dominant patterns. Your plan should be individualized and coordinated with your fertility team.

• Timing and expectations: Microbiome and endometrial immune support often need consistent work over weeks to months. For anyone planning IVF, it can be wise to allow a window to stabilize the uterine environment before transfer, when timelines allow.

  
  

A note of encouragement:

If you have had one or more losses, please know that you did not cause this. The goal is not to blame a single factor but to look for meaningful opportunities to support implantation and early placentation. A careful review of your history and a targeted plan can make this journey feel more guided and less overwhelming.

How our services can help:

As a Fertility Naturopath in Ottawa, I work alongside patients pursuing fertility treatments in Ontario, Quebec and numerous patients travelling across the globe to overseas fertility clinics to assess and support uterine health. Together we can decide if additional testing makes sense for you, discuss critical supportive strategies and design a step by step plan that supports a healthy and receptive lining.

Important notes:

Research is based on correlation and does not establish cause and effect. Supportive strategies for the endometrial microbiome can be considered due to their relatively high safety profile on a case-by-case basis if assessment determines it may be beneficial with careful evaluation and detailed discussion. Results can vary and testing is not always necessary.

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 Book a consultation to explore your symptoms and history in more depth. Together, we can create a targeted, compassionate, and proactive strategy to support your reproductive health.

Disclaimer: This blog is for informational purposes only and should not be taken as medical advice. Always consult with your Naturopathic Doctor before starting any new supplement, especially during fertility treatments like IVF.