Testing for chronic endometritis, a low-grade inflammation of the uterine lining, is something your doctor can consider after repeated failed transfers of good embryos, but it is not a proven fix. ESHRE’s 2023 good practice recommendations on recurrent implantation failure say assessment for chronic endometritis “can be considered,” and if it is diagnosed, antibiotic treatment “can be considered,” while noting the evidence is limited by inconsistent diagnostic standards and conflicting studies.
What chronic endometritis is
Chronic endometritis is persistent, usually silent inflammation of the endometrium, the lining where an embryo implants. Unlike acute pelvic infection, it rarely causes fever or pain. Most people find out only because they are being investigated after transfers that did not work, or after pregnancy loss.
The idea that it matters for IVF is biologically plausible: implantation depends on a carefully regulated immune environment in the lining, which our guide to endometrial receptivity explains. The open question is how often chronic endometritis is the real reason a transfer fails, and whether treating it changes outcomes.
How it is diagnosed
Endometrial biopsy with CD138 staining
The most common test is a small biopsy of the lining, done in the office. A pathologist looks for plasma cells, a type of immune cell not normally present in the endometrium. Because plasma cells can be hard to spot on standard staining, labs often use an immunohistochemical stain called CD138 that highlights them. The trouble is that labs do not agree on how many plasma cells, in how many fields, make the diagnosis, which is one reason studies disagree.
Hysteroscopy
During a hysteroscopy, a thin camera is passed through the cervix to look at the uterine cavity. Findings such as tiny polyps (“micropolyps”), swelling or patchy redness have been described in chronic endometritis. Hysteroscopy can also find polyps, fibroids, adhesions or a septum, which may matter more. Our guide to hysteroscopy before IVF covers when it helps and when it is optional.
Cultures and molecular tests
Some clinics culture the biopsy or use molecular tests that look for bacterial DNA in the lining. These are newer, less standardized and often sold as add-ons. Ask what decision the result would change before paying for one.
What ESHRE’s 2023 recommendations say
The European Society of Human Reproduction and Embryology published good practice recommendations on recurrent implantation failure (RIF) in 2023. Key points for this decision:
- Definition of RIF: repeated failure of embryos considered viable to produce a positive pregnancy test, to a degree that warrants investigation. ESHRE suggests counseling about further investigation once a patient’s estimated cumulative chance of implantation would have exceeded 60% without success.
- Chronic endometritis: assessment “can be considered”; if diagnosed, antibiotic treatment “can be considered.” Evidence is limited by inconsistent diagnostic standards and conflicting reviews.
- Hysteroscopy: can be considered, especially if a uterine abnormality is suspected on ultrasound. A randomized trial (TROPHY) in patients without known pathology found no difference in live birth rate with routine hysteroscopy.
- Endometrial receptivity tests: insufficient data to recommend routine use of any commercial receptivity test for RIF.
“Can be considered” is ESHRE’s middle category: not recommended for everyone, not ruled out. In practice it means testing is reasonable to discuss in the right situation, with honest expectations.
Why the studies disagree
If you read about chronic endometritis online, you will find claims that it affects a large share of people with failed transfers and that antibiotics “fix” it, alongside reviews concluding there is no clear benefit. Several things drive that disagreement:
- No single definition. Studies count plasma cells differently, so the same biopsy can be positive in one study and negative in another.
- Timing of the biopsy. Inflammatory cells vary across the menstrual cycle, and studies sample at different points.
- Who was studied. Groups range from first-time IVF patients to people with many failed transfers, with and without tested embryos.
- Comparison groups. Many studies compare treated patients with their own earlier failures rather than with randomized controls, which tends to make any treatment look better.
ESHRE’s cautious wording reflects exactly this. Until diagnosis is standardized and larger randomized trials report, it is reasonable to treat chronic endometritis as one possible contributor to check, not a common hidden cause.
Timing and cost
A biopsy is usually done in the cycle before a planned transfer, and if treatment and a repeat biopsy follow, the transfer may be delayed by a cycle or two. Ask whether the clinic will hold your transfer date and whether testing is covered by insurance, since some plans treat it as a diagnostic biopsy and others as an IVF add-on.
Who might reasonably consider testing
| Situation | Testing often discussed? | Why |
|---|---|---|
| Two or more failed transfers of good-quality or euploid embryos | Often | Embryo factors less likely; uterine factors worth reviewing |
| Recurrent pregnancy loss | Sometimes | Part of some evaluations; evidence also limited |
| Abnormal findings on ultrasound or prior hysteroscopy | Often | Inflammation may accompany other cavity problems |
| First transfer, no failures yet | Rarely | Routine testing is not supported |
| Failures with untested embryos at older ages | Less often | Embryo chromosomal factors are a more likely explanation |
Consider testing after repeated failures with good embryos, not before a first transfer.
- Usually discussed when
- Good-quality or tested embryos have failed to implant more than once.
- Main upside
- A treatable finding may be identified, and the biopsy is a short office procedure.
- Main tradeoff
- Diagnostic standards vary, and evidence that treatment improves live birth is limited.
Where it fits in the rest of the workup
Chronic endometritis is one item in a broader review after failed transfers. Others commonly discussed:
- Embryo factors: age, grading, and whether embryos were genetically tested.
- Cavity problems: polyps, fibroids, adhesions, septum; see FertileStart’s guide to the saline sonogram.
- Tubal fluid: a hydrosalpinx can lower IVF success.
- Lining preparation: thickness and hormone timing; see our guide to lining thickness before transfer.
- Receptivity and immune tests: often marketed, with limited support. Our reviews of ERA, EMMA and ALICE and NK cell testing look at the evidence.
HowToHaveABaby’s guides to what happens after a failed IVF cycle and recurrent pregnancy loss evaluation cover the emotional and practical next steps.
If you test positive
If a biopsy shows chronic endometritis, your doctor may discuss a course of antibiotics, sometimes followed by a repeat biopsy to check that the inflammation has cleared before the next transfer. Ask:
- How the diagnosis was made, and what threshold the lab used.
- Whether a repeat biopsy is planned, and whether the transfer will wait for it.
- What the plan is if the repeat biopsy is still positive.
- Whether your partner needs any testing or treatment.
If you test negative, that is useful information too: it moves attention to other possible causes rather than repeating the same test. Keep a copy of the pathology report with your records in case you change clinics.
- Do my history and embryo quality meet your threshold for investigating implantation failure?
- Would you test for chronic endometritis, and with which method?
- How would a positive result change my next transfer?
- Would you do a hysteroscopy, and is there a reason to suspect a cavity problem?
- Which other tests do you recommend now, and which do you think are not worth it?
- What is the cost of each test, and is it covered?
For the full menu of diagnostic tests, see our fertility testing hub.
- Failed IVF Cycle: What Happens Next and Your Options (HowToHaveABaby)
- Recurrent Pregnancy Loss Evaluation: Every Test and What It Means (HowToHaveABaby)
- Saline Sonogram (SIS): What It Finds, How It Differs from an HSG, and How to Prepare (FertileStart)
Compare how clinics handle implantation failure
Some patients compare accredited clinics in Colombia for a fresh look after failed transfers. Ask any clinic which tests it would run and why, and request a written all-in quote and its age-specific outcome data before deciding.
Questions? Message us on WhatsApp and we’ll point you to clinics and next steps. We may earn referral fees from partner clinics.
Frequently asked questions
What is chronic endometritis?
It is persistent, usually symptom-free inflammation of the uterine lining, typically diagnosed by finding plasma cells on an endometrial biopsy, often with CD138 staining.
Should everyone be tested for chronic endometritis before IVF?
No. ESHRE’s 2023 recommendations say testing can be considered in recurrent implantation failure; routine testing before a first transfer is not supported.
Do antibiotics for chronic endometritis improve IVF success?
Possibly for some patients, but evidence is limited and inconsistent. ESHRE says treatment can be considered if chronic endometritis is diagnosed.
Is the CD138 biopsy painful?
It is a brief office procedure, similar to other endometrial biopsies. Many people feel cramping; ask your clinic about pain relief.
What counts as recurrent implantation failure?
ESHRE describes it as repeated failure of viable embryos to implant to a degree that warrants investigation, suggesting counseling once the estimated cumulative chance of implantation would have exceeded 60%.
Sources & guidance
- ESHRE Working Group on Recurrent Implantation Failure. ESHRE good practice recommendations on recurrent implantation failure. Hum Reprod Open. 2023;2023(3):hoad023
- ESHRE: Recurrent implantation failure good practice recommendations (overview page)