Have you ever had a painful endometriosis flare and wondered, can endometriosis cause a fever? It is a reasonable question, especially when pelvic pain, fatigue, nausea, chills, or a general feeling of being unwell all appear at once.

The most accurate answer is usually no. A true fever is not considered a typical symptom of endometriosis. The World Health Organization lists symptoms such as severe menstrual pain, chronic pelvic pain, heavy bleeding, infertility, bloating, and nausea, but fever is not among the characteristic symptoms. World Health Organization

That does not mean the two can never occur together. Rare reports have described fever in people with endometriosis, and infections or other complications can produce fever alongside endometriosis. The important point is not to assume that every elevated temperature is simply another endometriosis symptom.

Can Endometriosis Cause a Fever?

Possibly—but the answer needs some nuance. Endometriosis is an inflammatory disease, and some people report low-grade temperature increases or flu-like, feverish symptoms around their period or during severe flares. However, fever is not considered one of the classic symptoms of endometriosis, so a persistent or high temperature deserves medical evaluation.

Endometriosis happens when tissue similar to the uterine lining grows outside the uterus. These lesions can respond to hormonal changes, become irritated, and trigger repeated local inflammation. ACOG explains that bleeding and inflammation around endometriosis lesions can lead to irritation, swelling, scarring, adhesions, and pain.

Think of it this way: endometriosis can create a persistent “fire” in the pelvis, but that local fire does not necessarily turn up the temperature of the entire body.

This is why a person can have severe endometriosis-related inflammation and pain without having a fever.

At the same time, medical literature contains reports of low-grade fever as a co-existing symptom in some people with endometriosis. That does not prove that endometriosis itself directly caused the fever, so it is important not to treat the two as automatically interchangeable.

What Counts as a Fever?

The NHS generally considers 38°C (100.4°F) or above to be a high temperature in adults. Body temperature naturally changes throughout the day, and factors such as the menstrual cycle can also produce smaller fluctuations.

So, a temperature that is slightly higher than your usual baseline is not necessarily a fever.

If you are tracking your temperature because you have endometriosis, note the actual number, the time of day, where you measured it, and whether you have other symptoms such as chills, pelvic pain, nausea, unusual vaginal discharge, urinary symptoms, or vomiting.

Is Fever a Typical Symptom of Endometriosis?

No. Fever is not a typical symptom of endometriosis.

Current guidance from NICE says clinicians should suspect endometriosis when patients have symptoms such as chronic pelvic pain, period-related pain, deep pain during or after sex, cyclical bowel or urinary symptoms, and infertility associated with these symptoms. Fever is not included in that core symptom list.

Similarly, the U.S. National Institutes of Health lists pain and infertility as the primary symptoms and also describes painful periods, pelvic or abdominal pain, painful bowel movements or urination, heavy periods, gastrointestinal symptoms, and fatigue.

The NHS describes a very similar pattern, focusing on pelvic and abdominal pain, painful periods, pain during sex or bowel movements, fatigue, bleeding problems, and fertility difficulties.

So if you have been diagnosed with endometriosis and suddenly develop a definite fever, it is better to look for another explanation rather than assume it is simply an endometriosis flare.

Why Can Endometriosis Cause Inflammation Without Causing Fever?

This is where the terminology can become confusing.

Endometriosis is a chronic inflammatory condition. Lesions can irritate surrounding tissues and contribute to pain, swelling, adhesions, and changes in the pelvic environment. WHO describes endometriosis as a chronic disease in which endometrium-like tissue outside the uterus causes inflammation and scar tissue formation.

But local inflammation and systemic fever are not the same thing.

A fever is a regulated rise in body temperature, often associated with infection or another systemic illness. Endometriosis may produce a strong local inflammatory response without triggering the body-wide temperature response that we recognize as fever.

Low-Grade Temperature Changes vs. a True Fever

There is an interesting nuance in the research.

A study involving women with surgically diagnosed endometriosis from the United States and Puerto Rico recorded “low grade fever” as a self-reported co-existing symptom. In the U.S. group, 37.6% of respondents reported it. However, this was a questionnaire-based observational study rather than a trial proving that endometriosis caused those temperature elevations. The U.S. participants also came largely from an endometriosis association population, which limits how broadly the findings can be applied.

So the evidence supports a careful conclusion:

Some people with endometriosis report low-grade fever or temperature changes, but that does not establish fever as a typical or direct symptom of endometriosis.

That is an important difference between saying “it has been reported” and saying “endometriosis causes it.”

What Can Cause a Fever If You Have Endometriosis?

If you have endometriosis and develop a fever, several possibilities should be considered.

Pelvic Inflammatory Disease or Another Pelvic Infection

One of the most important possibilities is pelvic inflammatory disease (PID) or another infection involving the reproductive organs.

ACOG lists “fever and chills” among the signs and symptoms of PID. PID can also cause lower abdominal pain, abnormal vaginal discharge, abnormal bleeding, painful urination, nausea, and vomiting.

This is a crucial distinction because endometriosis itself is not an infection. University College London Hospitals explicitly describes endometriosis as “not an infection, not contagious and not cancer.”

In other words, having endometriosis does not mean that a new fever is part of the disease. It may mean that something else is happening at the same time.

An Infected Endometrioma

An endometrioma, sometimes called an ovarian “chocolate cyst,” is a form of endometriosis involving the ovary. Most endometriomas are not infected, but secondary infection is a rare complication that has been documented in the medical literature.

Published case reports describe patients with infected endometriomas presenting with combinations of fever, pelvic pain, chills, nausea, elevated white blood cell counts, and pelvic or adnexal abnormalities.

This is uncommon, but it explains why a genuine fever should not simply be dismissed as “my endometriosis acting up.”

Urinary, Gastrointestinal, or Other Infections

The fever may also have nothing to do with the endometriosis itself.

For example, a urinary tract infection, kidney infection, gastrointestinal infection, respiratory virus, or another illness can cause a fever while you also happen to have endometriosis.

This matters because people with endometriosis may already be accustomed to pelvic discomfort. It can be easy to connect every new symptom to the diagnosis you already have.

That assumption can delay the right treatment.

Fever After Endometriosis Surgery

A fever after surgery deserves particular attention.

Cleveland Clinic advises contacting a healthcare provider after endometriosis surgery if a patient develops a fever of 101°F (38.3°C) or higher, particularly when accompanied by worsening pain, redness or swelling around an incision, pus drainage, heavy bleeding, or problems emptying the bladder.

Postoperative fever can have several causes, including infection, inflammation, or another complication. The appropriate response depends on when the fever started, how high it is, and what other symptoms are present.

What Other Symptoms Should You Watch For?

A fever becomes more concerning when it appears alongside symptoms that are not typical for your usual endometriosis pattern.

Pay particular attention to:

• Sudden or rapidly worsening pelvic or abdominal pain
• Chills or shaking
• Persistent vomiting
• Fainting, weakness, or significant dizziness
• New or foul-smelling vaginal discharge
• Pain or burning when urinating
• Heavy or unusual vaginal bleeding
• Significant abdominal swelling
• Fever following recent pelvic surgery

For example, ACOG notes that PID can cause fever together with pelvic pain, abnormal discharge, urinary symptoms, nausea, and vomiting.

The message is not that every combination means an emergency. It is that fever plus new or worsening pelvic symptoms deserves medical assessment rather than automatic attribution to endometriosis.

How Is the Cause of Fever Diagnosed?

There is no single test that answers the question, “Is my fever caused by endometriosis?”

A clinician will normally start with your medical history and a detailed symptom review. Timing matters. Did the fever begin during menstruation? Did it start suddenly? Have you recently had surgery? Do you have urinary symptoms, bowel symptoms, discharge, or respiratory symptoms?

Depending on the situation, assessment may include:

Medical History and Examination

A pelvic or abdominal examination can help identify tenderness, masses, or signs that point toward another pelvic condition.

Blood Tests

Blood tests may be used when infection or another systemic illness is suspected. They can help assess things such as white blood cell counts and inflammatory markers, although they do not diagnose endometriosis by themselves.

Ultrasound or MRI

NICE recommends transvaginal ultrasound for people with suspected endometriosis, including assessment for endometriomas and deep endometriosis and to look for other pathology that could explain symptoms. A normal ultrasound does not completely rule out endometriosis.

MRI may be useful in selected cases, particularly when deeper disease needs to be assessed and treatment planning requires more anatomical detail.

Specialist Evaluation

ACOG’s 2026 clinical practice guideline emphasizes clinical assessment, imaging, and surgical evaluation when appropriate. It also supports making a clinical or presumptive diagnosis from symptoms, history, and examination while evaluation continues.

The key point is simple: fever should be investigated on its own clinical merits rather than used as proof for or against endometriosis.

When Should You See a Doctor About Fever and Endometriosis?

You should seek medical advice when you have a measured fever alongside pelvic pain, especially if the pain is new, severe, or different from your usual endometriosis symptoms.

You should also be assessed promptly if fever occurs after endometriosis surgery, or if it comes with chills, vomiting, unusual vaginal discharge, urinary symptoms, heavy bleeding, severe weakness, or rapidly worsening abdominal pain.

And remember: you do not need to wait until your symptoms become unbearable before asking for specialist help. NICE recommends further assessment or referral when suspected or confirmed endometriosis remains persistent, recurrent, significantly affects everyday life, or does not respond adequately to initial treatment.

Endometriosis Care With Dr. Lucas Minig in Valencia, Spain

For patients who need specialist evaluation of complex endometriosis, Dr. Lucas Minig’s practice in Valencia provides a multidisciplinary approach that combines clinical assessment with medical management and minimally invasive surgery when appropriate. The clinic’s endometriosis service describes care for conditions including deep endometriosis, ovarian endometriomas, bowel, bladder, and ureter involvement, as well as laparoscopic and robotic surgical approaches in selected patients.

The practice also supports patients coming from outside Spain through teleconsultations and international-patient coordination, which can be useful when someone wants to discuss a complex diagnosis or treatment plan before deciding whether travel to Valencia makes sense.

For someone searching “can endometriosis cause a fever,” the priority should still be identifying the cause of the fever. Specialist endometriosis care becomes especially relevant when pelvic pain is persistent, disease is suspected to be deep or complex, an endometrioma is present, or previous treatment has not provided adequate relief.

Conclusion

So, can endometriosis cause a fever? Usually, not as a typical feature of uncomplicated endometriosis. Endometriosis is inflammatory, but its classic symptoms are pelvic pain, painful periods, pain with sex or bowel and bladder movements, heavy bleeding, fatigue, and fertility problems. Some patients have reported low-grade fever or temperature changes, but the evidence does not show that ordinary endometriosis routinely causes a true fever.

A genuine fever—particularly around 38°C (100.4°F) or higher—should make you consider infection, an infected endometrioma, another illness, or a postoperative complication rather than simply blaming endometriosis.

FAQs

Can endometriosis cause a low-grade fever?

Some women with endometriosis have reported low-grade fever or mild temperature changes, but this is not considered a classic symptom. A persistent or measured fever should still be assessed to rule out infection or another cause.

Can endometriosis cause chills?

Chills are not a typical feature of uncomplicated endometriosis. Chills combined with fever and pelvic pain are more concerning for infection, including pelvic inflammatory disease, and warrant medical evaluation.

Is 38°C a fever if you have endometriosis?

Yes. The NHS generally considers 38°C (100.4°F) or above a high temperature in adults. Having endometriosis does not change that definition, and a true fever should not automatically be assumed to come from endometriosis.

Can an endometrioma cause a fever?

An ordinary endometrioma does not usually cause fever, but secondary infection of an endometrioma is a rare documented complication. Fever with significant pelvic pain, chills or other signs of infection needs prompt medical assessment.

Should I seek urgent care for fever with pelvic pain?

You should seek prompt medical assessment when fever occurs with severe or worsening pelvic pain, chills, vomiting, unusual vaginal discharge, urinary symptoms, heavy bleeding, or after recent surgery.