Chronic endometritis is a long-lasting, low-grade inflammation of the womb lining (endometrium), usually caused by bacteria. Most women have no symptoms at all, yet it can make it harder for an embryo to implant and is linked with repeated IVF failure and recurrent miscarriage. It is found with a hysteroscopy and a small biopsy of the lining, and it is usually treated with a course of antibiotics, followed by a repeat test to make sure it has cleared. At Yaal Fertility Centre in Chennai, Dr. Rukkayal Fathima and our team look for it when good embryos repeatedly fail to implant.
What Is Chronic Endometritis?
The endometrium is the soft inner lining of the womb. Each month it thickens to prepare for a pregnancy and sheds as a period if no embryo implants. An embryo has to attach to this lining and burrow into it, so the health of the lining matters as much as the quality of the embryo.
In chronic endometritis, bacteria settle in the lining and keep the body's immune system switched on at a low level. The immune system sends plasma cells, a type of white blood cell that makes antibodies, into the lining. A healthy lining has almost none of these cells. When they are present in numbers, they are the sign doctors look for.
Because the inflammation is mild, there is no fever, no sudden pain and nothing obvious on a routine scan. That is why many women only find out they have it after several unexplained setbacks.
Chronic vs Acute Endometritis
The two share a name but behave very differently.
| Acute endometritis | Chronic endometritis | |
|---|---|---|
| When it happens | Suddenly, usually after delivery, a miscarriage, an abortion or a procedure on the womb | Slowly, over months or years |
| How it feels | Fever, severe lower tummy pain, foul-smelling discharge, feeling unwell | Usually nothing; sometimes mild spotting or a dull ache |
| What it needs | Urgent medical care, sometimes hospital admission | Planned tests and a course of antibiotics |
| Effect on fertility | Mostly temporary, though severe infection can leave scarring | Can stop implantation and raise miscarriage risk while it lasts |
If you have fever and severe pain after childbirth, a miscarriage or a procedure, see a doctor the same day. That is not chronic endometritis, and it should not wait.
Chronic Endometritis vs Endometriosis
The names sound alike, and patients often confuse them, but they are completely different conditions.
| Chronic endometritis | Endometriosis | |
|---|---|---|
| What it is | Inflammation of the lining inside the womb | Lining-like tissue growing outside the womb |
| Where | The womb cavity | Ovaries, tubes, the pelvic lining, bowel |
| Cause | Usually bacteria | Not an infection; the cause is not fully known |
| Typical symptoms | Often none | Painful periods, pain during sex, pelvic pain |
| How it is found | Hysteroscopy and lining biopsy | Scan, MRI, laparoscopy |
| Treatment | Antibiotics | Pain relief, hormones, surgery or IVF |
A woman can have both, and each needs its own plan. For the full picture on endometriosis, read our guide to endometriosis and fertility.
What Causes Chronic Endometritis?
The womb is not completely sterile. A healthy reproductive tract has its own balance of "good" bacteria, mostly Lactobacillus. Chronic endometritis develops when other bacteria move up from the vagina and cervix and settle in the lining.
Bacteria Involved
- Common gut and skin bacteria, such as E. coli, Enterococcus, Streptococcus and Staphylococcus. These are the most frequent culprits.
- Mycoplasma and Ureaplasma, small organisms that live in the genital tract.
- Sexually transmitted infections, such as chlamydia and gonorrhoea, in a smaller number of women.
- Bacteria linked with bacterial vaginosis, an imbalance of vaginal bacteria that is very common and not a sign of anything wrong in a relationship.
Risk Factors
- A past pelvic infection, including pelvic inflammatory disease.
- Procedures on the womb, such as a D&C, hysteroscopy or polyp removal.
- A miscarriage, especially if some pregnancy tissue stayed behind.
- Childbirth, particularly after a long labour or caesarean section.
- A coil (IUD) left in place for a long time.
- Repeated vaginal infections.
Many women with chronic endometritis have none of these, so the absence of risk factors does not rule it out.
Genital Tuberculosis Is a Different Condition
Tuberculosis can also infect the womb lining and tubes, and it is still seen in India. It causes much more damage than ordinary chronic endometritis, including scarring inside the womb and blocked tubes, and it needs a full course of TB medicines rather than standard antibiotics. The tests are different too. If your doctor suspects it, read our guide to genital tuberculosis and infertility.
Chronic Endometritis Symptoms
Most women with chronic endometritis feel completely well. Periods are normal and scans look normal. When symptoms do appear, they are mild and easy to put down to something else.
Possible Signs
- Light spotting between periods, or brown spotting before a period starts.
- Spotting after sex.
- A dull ache low in the tummy that does not follow a monthly pattern.
- Unusual vaginal discharge that keeps coming back even after vaginal infections have been treated.
- Pain during sex, in some women.
None of these is specific. Spotting, for example, is far more often caused by hormones, polyps or a thin lining. The more telling "symptom" is usually a pattern of fertility problems.
When Doctors Become Suspicious
- Two or more failed embryo transfers with good-quality embryos.
- Two or more miscarriages without a clear cause.
- Unexplained infertility after the usual tests are normal.
- Findings on hysteroscopy such as tiny polyps or a red, swollen lining.
Some women wonder whether early spotting after a transfer is a sign of a problem. Our guide to implantation symptoms explains what is normal in those early days.
How Chronic Endometritis Affects Implantation and Pregnancy
For an embryo to implant, the lining has to be "receptive" for a short window each cycle. During that window, the lining and the embryo exchange chemical signals, and the immune system in the womb shifts to welcome the pregnancy rather than attack it.
Chronic inflammation upsets this balance:
- The immune environment changes. The lining fills with inflammatory signals that make it less welcoming to an embryo.
- The lining does not mature properly. Before implantation, cells in the lining change into a special supportive tissue. Inflammation can stop this change happening fully.
- Blood supply can be affected. Small blood vessels in an inflamed lining may not develop normally, which matters for the early placenta.
The result can be an embryo that does not attach at all, or one that attaches but does not hold, leading to a very early loss (sometimes only seen as a briefly positive pregnancy test) or a miscarriage.
Chronic Endometritis and Recurrent Miscarriage
Studies have found chronic endometritis more often in women with repeated miscarriages than in women without them. It is one of several things doctors check, alongside chromosome tests, blood clotting conditions, thyroid problems and the shape of the womb. Our guide to recurrent pregnancy loss covers the full list of tests.
Endometritis and IVF
IVF lets doctors see exactly how good an embryo is before transfer. So when high-quality embryos, sometimes even genetically tested ones, fail again and again, attention turns to the womb.
Its Role in Recurrent Implantation Failure
Recurrent implantation failure means no pregnancy after several good embryos have been transferred. Research has found chronic endometritis in a sizeable share of women in this situation, though figures vary widely between studies because centres use different tests and cut-offs. It is one of the most common treatable womb causes.
It is not the only one. Polyps, fibroids, scar tissue, a thin lining and a shifted implantation window can all play a part. Read our guide to recurrent implantation failure for how these are checked together, and why IVF fails for the wider picture, including embryo factors.
Should Everyone Be Tested Before IVF?
No. Testing every woman before a first IVF cycle is not routine. It is usually considered after repeated failed transfers or miscarriages, or when a hysteroscopy shows signs of inflammation. Your doctor will weigh up your history before suggesting it.
How Is Chronic Endometritis Diagnosed?
A routine ultrasound cannot see chronic endometritis, because the changes are microscopic. Diagnosis relies on looking inside the womb and testing a small piece of the lining.
Hysteroscopy
A hysteroscopy uses a thin telescope with a camera, passed gently through the cervix, to look directly at the inside of the womb. No cuts are needed. Signs that suggest chronic endometritis include:
- Micropolyps: many tiny bumps, each smaller than a millimetre.
- Redness: patches of red, congested lining, sometimes with a dotted "strawberry" look.
- Swelling: a thick, pale, puffy lining.
These findings raise suspicion, but they do not confirm the diagnosis on their own. The doctor usually takes a biopsy during the same procedure. Read more in our guide to hysteroscopy for fertility.
Endometrial Biopsy
A biopsy takes a very small sample of the lining, either during hysteroscopy or as a quick outpatient test with a thin, flexible tube passed through the cervix. It causes cramping for a short time, similar to a strong period pain. The timing in your cycle matters, and your doctor will tell you which days are best.
CD138 Staining, Explained Simply
In the laboratory, the sample is treated with a special stain called CD138. This stain sticks only to plasma cells and colours them brown, so they stand out clearly under the microscope. Without the stain, plasma cells can be hard to tell apart from normal cells in the lining.
If the pathologist finds plasma cells above a set level, the diagnosis is confirmed. Laboratories use slightly different cut-offs, which is one reason results should always be read by your fertility doctor.
Other Tests
- Culture or DNA tests on the sample can sometimes identify the specific bacteria, which can help choose the antibiotic.
- Swabs for sexually transmitted infections and bacterial vaginosis.
- TB tests if genital tuberculosis is a possibility.
Chronic Endometritis Treatment
The good news is that chronic endometritis is usually treatable with medicines you take at home.
Antibiotics
Treatment is a course of oral antibiotics, usually lasting around two weeks. The choice of antibiotic depends on your history and any bacteria found on testing. If the first course does not clear the inflammation, a different antibiotic or a combination is used. Your doctor will prescribe the exact medicine and schedule. Do not take antibiotics on your own or stop a course early, as this can leave the infection partly treated.
Mild side effects such as an upset stomach are common. Tell your doctor if you have allergies to any antibiotic.
Treating Your Partner
If a sexually transmitted infection is found, your partner needs treatment too, even if he has no symptoms. Otherwise the infection can pass straight back. Your doctor will usually advise avoiding sex until you have both finished treatment. For most bacteria that cause chronic endometritis, partner treatment is not needed, and your doctor will explain which applies to you.
Supporting Healthy Bacteria
Some doctors suggest probiotics containing Lactobacillus after antibiotics to help restore a healthy balance. Research on this is still developing, so take them only if your doctor advises it.
Retesting After Treatment
Finishing the antibiotics does not always mean the inflammation has gone. A proportion of women need a second course. For this reason, many fertility doctors repeat the biopsy (and sometimes the hysteroscopy) after treatment, before planning another embryo transfer. This is often called a "test of cure".
If the repeat test is clear, you can move on. If plasma cells are still present, a second antibiotic course is given and the test repeated again. Retesting takes some extra weeks, but it avoids using precious embryos in a lining that is still inflamed.
IVF and Pregnancy After Treatment
Once the lining is clear, the next step depends on your plan.
Frozen Embryo Transfer
If you have frozen embryos, a transfer is usually planned in a following cycle. The lining is prepared with hormones or timed with your natural cycle, and monitored by scan until it is ready. If your lining tends to be thin, our guide on how to increase endometrial thickness explains what can help.
A Fresh IVF Cycle
If you need a new cycle, stimulation can start once treatment and retesting are done. Your doctor may suggest freezing all embryos and transferring later, to allow the lining to be checked first.
Trying Naturally
Women who are not doing IVF can usually try again naturally after treatment, once the doctor confirms it is safe. If there have been miscarriages, a plan for early pregnancy scans and support is worth discussing in advance.
What to Expect
Studies suggest that women whose chronic endometritis is cured have better implantation and pregnancy chances in later cycles than those whose inflammation persists. Treatment removes one barrier, but it cannot fix embryo or other womb factors, so it is part of a complete evaluation rather than a cure-all.
Can Chronic Endometritis Be Prevented?
Not always, since many women develop it without any known cause. A few steps lower the risk:
- Get vaginal infections treated promptly and completely.
- Practise safe sex and get tested if you or your partner may have been exposed to an infection.
- Report symptoms after a procedure, such as fever, foul discharge or worsening pain, so infection is treated early.
- Have a coil checked or changed as advised, rather than leaving it in long past its time.
Questions to Ask Your Doctor
- Could chronic endometritis be one reason my transfers have failed or I have miscarried?
- Do I need a hysteroscopy, a biopsy, or both?
- When in my cycle should the biopsy be done?
- Does my partner need any tests or treatment?
- Will you repeat the biopsy after antibiotics?
- How soon after treatment can we plan the next transfer?
Frequently Asked Questions About Chronic Endometritis
Can chronic endometritis go away on its own?
It rarely clears without treatment, because the bacteria tend to stay in the lining. A course of antibiotics prescribed by your doctor is usually needed.
What are the most common chronic endometritis symptoms?
Most women have no symptoms. When present, they are mild: spotting between periods or after sex, a dull pelvic ache or recurring unusual discharge.
Is chronic endometritis the same as endometriosis?
No. Chronic endometritis is inflammation inside the womb, usually from bacteria. Endometriosis is lining-like tissue growing outside the womb and is not an infection.
Is the endometrial biopsy painful?
Most women feel cramping for a short time, similar to period pain. Your doctor may suggest a simple painkiller beforehand.
Can chronic endometritis cause miscarriage?
It is linked with a higher chance of early pregnancy loss and recurrent miscarriage. It is one of several causes doctors check after repeated losses.
How long after treatment can I have an embryo transfer?
Usually once a repeat test confirms the lining is clear, often in a cycle soon after. Your doctor will set the timing based on your results.
Does chronic endometritis affect egg quality or AMH?
No. It affects only the womb lining, not the ovaries, so egg numbers and quality are not changed.
Can it come back after treatment?
It can, especially after new infections or procedures on the womb. Treating both partners when needed and getting infections seen early lowers the risk.
Chronic Endometritis Care at Yaal Fertility Centre, Chennai
At Yaal Fertility Centre, our IVF team led by Dr. Rukkayal Fathima, MRCOG (UK) looks at the womb as carefully as the embryo. If transfers have failed or pregnancies have been lost, we review your history, discuss whether a hysteroscopy and lining biopsy make sense for you, and plan treatment and retesting before your next step, explaining each result in plain words.
You can see our team at any of our eight centres across Chennai: Kilpauk, Mylapore, Thiruvanmiyur, Pallikaranai, Madipakkam, Red Hills, Velappanchavadi and Tambaram.
If you have had failed embryo transfers or repeated miscarriages and want to know whether your womb lining is part of the picture, book a consultation with Yaal Fertility Centre.
Written by
Dr. Rukkayal Fathima
Specialist at Yaal Fertility Centre, Chennai. Providing expert guidance on fertility and women's health.
