Chronic Endometritis: What It Means and How We Manage It

Chronic endometritis is a low-grade, often symptomless inflammation of the uterine lining (endometrium). It’s surprisingly common — and in recent years, it’s been increasingly recognised as one of the possible “missing pieces” in fertility care.

While it doesn’t cause pain or obvious symptoms for most women, chronic endometritis may make it harder to conceive, especially if you’ve had repeated implantation failure, miscarriages, or unexplained infertility. The good news? It’s treatable.

Let’s walk through what it means, how we diagnose it, and how we approach treatment.

What is Chronic Endometritis?

Chronic endometritis isn’t an infection in the traditional sense — it’s not something you’d usually feel unwell from. Instead, it’s a persistent immune reaction in the lining of the uterus, often triggered by low levels of bacteria that don’t normally cause symptoms.

This subtle inflammation can interfere with how receptive the uterine lining is to an embryo, which may reduce the chance of implantation or increase the risk of miscarriage. It can also affect the uterine environment in ways that are not yet fully understood.

How Do We Diagnose It?

Diagnosis involves a small biopsy of the endometrium, usually performed during a standard cycle.

In the lab, we look for immune cells (called plasma cells) using a special stain (CD138) — this is the gold standard for diagnosis. Sometimes a hysteroscopy is also used to visualise the uterine cavity, especially if we suspect structural issues or inflammation.

In selected cases, we may also offer molecular testing like the EMMA (endometrial microbiome) and ALICE(bacterial pathogen panel) tests. These are additional tools that can give insight into the bacterial balance of the uterine lining.

What Are the Fertility Implications?

Even without symptoms, chronic endometritis may:

• Reduce the likelihood of embryo implantation in IVF
• Contribute to early miscarriage
• Disrupt the delicate hormonal and immune signals needed for conception

We don’t screen every patient for chronic endometritis. But if you’ve had recurrent implantation failure, recurrent miscarriage, or unexplained infertility, we may recommend testing as part of your fertility assessment.

How Is It Treated?

Treatment is usually simple and well tolerated.

We prescribe a course of oral antibiotics — most commonly doxycycline — for 10 to 14 days. In some cases, we may tailor antibiotics to specific bacteria if test results suggest this is helpful.

Some patients may also benefit from probiotic strategies designed to rebalance the endometrial microbiome, although this is still an emerging area of research. These are always discussed on a case-by-case basis.

Do I Need a Repeat Biopsy After Treatment?

This depends on your history and fertility plan.

Some patients may choose to have a repeat biopsy after treatment to confirm that the inflammation has cleared — especially if you’re preparing for IVF or have had previous failed cycles.

Others may move straight to treatment or embryo transfer, particularly if your clinical picture has improved. There’s no one-size-fits-all answer here — we’ll help guide you based on your situation.

Advantages of repeat biopsy:

• Confirms that treatment has worked
• Reassures before starting IVF or a frozen embryo transfer

Disadvantages:

• Involves another minor procedure
• May delay treatment by 1 cycle

Together, we’ll decide if repeating the biopsy is worthwhile in your case.

What About EMMA and ALICE?

These are advanced tests that analyse the bacteria present in the endometrial lining.

• EMMA looks at the microbiome — the overall bacterial balance in your uterus.
• ALICE looks for specific bacteria linked to chronic endometritis.

These tests are helpful in some cases — particularly where there’s a pattern of repeated IVF failure or if biopsy results are inconclusive. They aren’t needed for everyone but may offer another layer of insight in more complex fertility journeys.

Final Thoughts

Chronic endometritis is a silent condition — and one that may go unnoticed without testing. But when it’s found and treated, it can make a real difference to implantation, pregnancy outcomes, and overall fertility confidence.

If you’ve been trying to conceive and haven’t found a clear explanation yet, talk to your doctor about whether testing for chronic endometritis could be a helpful next step