Endometriosis: a common condition the world doesn't seem to understand

Antonio Gargiulo, MD - Contributor Avatar

Reviewed by Antonio Gargiulo, MD, 

Antonio Gargiulo, MD - Contributor Avatar

Reviewed by Antonio Gargiulo, MD, 

last updated: Dec 27, 2021

10 min read

The World Health Organization (WHO) reports that about 1 in every 10 people with ovaries in the world has endometriosis. Despite how common endometriosis is, misinformation and misdiagnosis is just as pervasive.

In this article, we're raising awareness and promoting clinically accurate info about the condition — one that can cause serious pain and distress for the people who have it.The biggest takeaways

  • Endometriosis is a condition where tissue that's similar to the lining of the uterus (aka the endometrium) is discovered outside of the uterus.

  • While most people with endometriosis have ovaries and are in their reproductive years, cases have been documented in those who are much younger, older, or even people who produce sperm.

  • The most common symptoms of endometriosis are painful periods and painful ovulation.

  • In the US, diagnosis of endometriosis can take an average of 7.5 years after the first symptom because of limited endometriosis awareness and stigma around female pain.

  • The only way to treat endometriosis itself (not just minimize symptoms) is to fully remove the tissue through surgery with a surgeon who specializes in the condition.

  • Endometriosis can cause infertility, but early treatment and working with a specialist who's committed to preserving fertility can improve the chances of getting pregnant. In some cases, fertility treatment may be recommended.

Keep reading to find out more about this common but poorly understood condition.

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What is endometriosis?

Endometriosis is an estrogen-dependent, inflammatory condition where tissue that's similar to, though not the same as, the lining of the uterus (aka the endometrium) is discovered outside of the uterus. This may happen on the:

  • Ovaries (the most common)

  • Fallopian tubes

  • Bladder

  • Bowel

  • Intestines

  • Colon

  • Rectum

  • Appendix

The severity of endometriosis can be broken down into four different stages (stage I, stage II, stage II, stage IV) based on two scoring systems currently adopted. One which is a classic scoring system by the American Society for Reproductive Medicine, where stages correlate with the chance of experiencing infertility; another one by the American Association of Gynecologic Laparoscopists, which is based on the true complexity of surgical treatment (this is a new scale as of 2021!). The higher the score, the higher the stage number. These stages are an indication of severity, but experts don't know if stages are truly different phases of the same condition or if mild and severe forms represent different conditions altogether.

"If you operate well on endo, the chance of a recurrence of endometriosis should be much less. [But if it comes back], you are likely to see endometriosis of the same stage," explains Dr. Antonio Gargiulo, MD, a reproductive endocrinologist and minimally invasive gynecologic surgeon at Brigham and Women's Hospital and Harvard Medical School who specializes in treating endometriosis and other conditions associated with pelvic pain. "That's probably because the mild forms and the severe forms are in fact different conditions."

Who gets endometriosis?

The vast majority of people with endometriosis have ovaries and are in their reproductive years. Still, cases have been documented in people who haven't gotten their periods yetpostmenopausal peoplepeople who've had hysterectomies (surgical removal of the uterus), and in extremely rare cases in people with sperm and one fetus.

What are the symptoms of endometriosis?

"There is no question that the most common presentation of endometriosis is those with painful periods and painful ovulation. Then painful intercourse, then painful defecation, painful urination," says Dr. Gargiulo. "Then pain outside of any specific physiologic act. It's usually a crescendo that can be a very, very slow slope. It can really surprise the patient herself."

Other possible symptoms of endometriosis include:

  • Diarrhea or constipation

  • Bloating

  • Heavy or irregular bleeding

  • Fatigue

  • Scar tissue

  • Adhesions

  • Infertility (more on this later)

What causes endometriosis?

There are a lot of theories for the cause of endometriosis, but none have been fully proven. Some hypotheses, like retrograde menstruation (the idea that menstrual tissue might flow back into the fallopian tubes and grow on organs) have been challenged.

"The knowledge of the cause of endometriosis, at this point, has no clinical value for patients or doctors," explains Dr. Gargiulo. "The theories really don't help much until something radical comes out, allowing the treatment to radically change." That said, according to Dr. Gargiulo, the development of endometriosis is most likely due to immunological dysregulation.

How is endometriosis diagnosed?

In the US, it can take 4-11 years (an average of 7.5) after the first symptom of endometriosis to get a diagnosis. Dr. Gargiulo boils this problem down to two main factors: a lack of endometriosis awareness and the way pain is typically treated.

The importance of endometriosis knowledge

“Endometriosis is a condition that disproportionately affects young patients, who spend a significant amount of time on the internet," explains Dr. Gargiulo. "That means that they have access to knowledge. Contrary to Alexander Pope’s eighteenth century maxim that 'a little knowledge is a dangerous thing,' in the case of young patients and endometriosis, 'a little knowledge' can be a lifesaver." Dr. Gargiulo says that the long interval between first symptom and diagnosis can be shortened by access to clinically sound information on the internet and patients driving their own care. (Around 85% of Dr. Gargiulo's patients with endometriosis come in without being referred by a doctor.)

Misconceptions on the provider side

"When I trained 30 years ago, there was a lot of misconception regarding pelvic pain — and, unfortunately, these days at some levels of American medicine, it's still there," Dr. Gargiulo says. But, he adds, "Pain is not measurable. You don't have a painometer — it's not blood pressure, it's not your pulse, it's not your temperature."

A diagnosis of endometriosis requires "a patient that can communicate effectively — and a doctor that wants to listen and understands that endometriosis is extremely prevalent. Because, truly, endometriosis is probably much more common than idiopathic (i.e., not associated with a known cause) dysmenorrhea," Dr. Gargiulo explains. "That means that a woman that has very severe pelvic pain associated with ovulation and menses most likely has endo, not benign idiopathic dysmenorrhea. Also, we should be very prompt to recognize that that severe pelvic pain that is cyclical is basically never 'in her head.'"

It's for all of the above reasons that, according to Dr. Gargiulo, only two types of medical professionals are equipped to treat people with endometriosis: reproductive endocrinologists and gynecologists with special training in advanced minimally invasive gynecologic surgery. "Among these, patients can more easily and safely select providers who have a special interest in endometriosis," he says.

So, when endometriosis is diagnosed, how does that happen?

Back in the '90s, laparoscopic surgery was required to fully visualize the pelvis and give a diagnosis. Now, explains Dr. Gargiulo, the ideal method is imaging before potential surgery: either through high-specialty ultrasound or high-specialty MRI. "The endometriosis specialist will know where to send you for high-level endometriosis imaging," he says. "In fact, if you see them after already having such tests done at a non-specialized radiology center, they will most likely have you repeat the imaging tests."

How is endometriosis treated?

Endometriosis treatment either treats the condition's symptoms (medication and pelvic floor physical therapy) or removes the condition (surgery).

Treating symptoms with medication

Since endometriosis is an estrogen-dependent condition, the medications prescribed to manage painful period symptoms contain synthetic hormones. These include:

  • Combination estrogen-progestin therapy (the pill, vaginal ring, or the patch)

  • Progestin-only therapy (the minipill or progestin-delivering intrauterine device)

  • Androgen therapy (Danazol, which is no longer prescribed except in very rare cases)

Other synthetic hormonal medications include those that act on the pituitary gland (in the brain) to stop ovarian function, such as leuprolide (Lupron) or elagolix. However, due to the fact that leuprolide and elagolix have significantly harmful effects on bone density, they're not sustainable as treatment and are very rarely prescribed. "Basically, by the time patients are dealing well with side effects and are enjoying the benefits of these treatments, it is time to stop it," says Dr. Gargiulo.

If you have endometriosis and you're considering having kids in the near future, managing your symptoms with hormonal medications only may delay surgery — which could be a more effective step in improving fertility. Waiting on surgery could also potentially lead to a worsening of tubal or ovarian damage, making conception even more challenging. The decision of when to intervene surgically is therefore a delicate and very meaningful one.

Treating the condition with minimally invasive surgery

"There are many ways to skin a cat, and for endometriosis, there is only one correct way to do it — which is to excise the endometriosis," explains Dr. Gargiulo. "Endometriosis must be physically removed from the body, and no endometriosis should be left in place." The open surgeries of the past, which were the norm for the “frozen pelvis” picture of stage IV endometriosis, have been replaced with advanced laparoscopic (minimally invasive) and robotic surgery. “If anybody should ever tell you that your endometriosis can only be operated on via open surgery, they are being honest with you: They mean to say that they will open you," says Dr. Gargiulo. "That is your hint to seek a second opinion right away."

If you think you might have endometriosis, Dr. Gargiulo's recommendation is to go to an expert physician for a risk assessment. If testing indicates you do have endometriosis and surgery is advised, it's important to seek out a surgeon who specializes in treating the condition. This is because of the inherent complexity in endometriosis surgery. "Endometriosis will persist or recur if not completely excised, and may even come back when completely excised," he explains. "Even the best case-series from excision, albeit showing excellent results, report on rates of reoperation."

According to Dr. Gargiulo, "there's a conglomerate of vital organs around endometriosis: rectum, ureters, bladder. As an endometriosis surgeon, you have to be able to negotiate your way through these organs to be able to operate with absolute comfort in the retroperitoneal spaces — beyond the anatomical limits of the abdominal cavity." Working with a surgeon who specializes in endometriosis, or with a specialized team of surgeons, will make sure that the condition is fully removed and will limit the chance of needing an open surgery even in high-complexity cases. "Full excision of endometriosis by minimally invasive surgery is basically always possible in the right hands," says Dr. Gargiulo.

The role of pain management and alternative medicine

"Pelvic floor physical therapy is an essential component of the modern management of endometriosis-related pelvic pain," says Dr. Gargiulo. "The timing and extent of this treatment modality varies depending on provider and patient preference. Post-surgical pelvic PT is considered an essential complement to surgical treatment in specialized centers."

However, adds Dr. Gargiulo, "In spite of our best efforts with targeted and sustainable hormonal treatment, surgical excision, and pelvic floor intervention, some patients will not regain a completely pain-free life experience. We refer these patients to specialized pain management centers, and work very successfully with our anesthesiologist and neurologist colleagues."

Some people with endometriosis may also find relief from acupuncture — and there's some evidence it can be helpful in treating pain related to the condition. If acupuncture is helpful for you and you can afford it, that's really all that matters.

How can endometriosis impact fertility?

In 2012, the American Society of Reproductive Medicine (ASRM) published a committee opinion citing that as many as 50% of people with endometriosis also have infertility — and as many as 50% of people with infertility have endometriosis.

Some important context here is that many people don't realize they have endometriosis for a long time — owing to a general lack of awareness about the condition and the slow crescendo of worsening symptoms. "Endometriosis can negatively impact fertility without giving any other signs of its presence. This clinical scenario of 'silent endometriosis' is likely more common than generally recognized," says Dr. Gargiulo. "Reproductive endocrinology and infertility specialists are very aware of this possibility, and keep endometriosis in mind even when dealing with apparently 'unexplained' infertility and recurrent pregnancy loss."

There are a few ways to understand the connection between endometriosis and infertility.

Endometriosis and ovarian reserve

Anti-Mullerian hormone (AMH) is the best lab indicator we have for ovarian reserve, or how many eggs you have — and it may also potentially provide insight into endometriosis. While people with endometriosis can have a range of AMH levels, research points to an association between the condition and low AMH or diminished ovarian reserve (DOR). If your AMH is low compared to other people your age, you likely have a lower egg count and possibly a shorter reproductive window (and earlier menopause onset).

Having surgery on ovarian endometriosis (when endometrium-like tissue is discovered on or inside the ovaries) can also lower ovarian reserve. Even with the very best surgeons, the best surgical techniques, and ovary reconstruction, Dr. Gargiulo explains that you're going to lose some of your ovary every time you undergo a procedure to excise ovarian endometriosis. This is why who you choose as your doctor is especially important. "You want to make sure that your surgeon is a surgeon that is all about fertility sparing," says Dr. Gargiulo. This means "considering endometriosis affecting the ovaries as a fertility-preservation emergency. If this is not recognized, the patient is being failed." Fertility should be kept in mind before and after surgery.

Because of the link between ovarian reserve and endometriosis, fertility cryopreservation (eggs, embryos, ovarian tissue) may be recommended — and AMH is routinely tested in every patient who has known ovarian endometriosis or who's having surgery on ovarian endometriosis.

Endometriosis and egg quality

Studies have also shown that endometriosis can have an impact on egg quality. One 2017 systematic review of the available data found that the eggs of people with endometriosis are less likely to mature enough to be used successfully in fertility treatment and may also have issues with morphology (shape). As a result, people with endometriosis may have lower rates of success with in vitro fertilization (IVF) — and those with more mild cases might see lower rates of successful egg fertilization.

One possible explanation for the condition's effects on egg quality is inflammation — which experts aren't sure is a factor in or result of endometriosis. Regardless of the exact reason this happens, inflammation can alter egg (as well as sperm, embryo, and fallopian tube) function.

Endometriosis and tubal damage

If endometriosis is present in the fallopian tubes, that can lead to scar tissue or adhesions that obstruct the affected tube. This can make it more difficult for eggs to travel through the tubes on their way to getting fertilized by sperm in the reproductive tract.

Can you still get pregnant if you have endometriosis?

Yes! For the 50% of people with endometriosis who have issues getting pregnant, undergoing fertility-sparing surgery with a surgeon who specializes in treating the condition will likely be the best path forward.

After surgery, what happens next depends on the circumstances:

  • Expectant management: For people under 35 who had minimal or mild endometriosis, expectant management (aka "watchful waiting") — or essentially waiting and seeing if the person can get pregnant without treatment — may be an option.

  • Controlled ovarian stimulation (COS) with intrauterine insemination (IUI): Those with minimal or mild endometriosis may also opt for COS (aka superovulation) with IUI to increase chances of conception. In COS with IUI, fertility medications (like clomiphene citrate or hormonal injections) are used to stimulate egg maturation — then a healthcare provider will place sperm directly into the uterus just before ovulation.

  • In vitro fertilization (IVF): People with moderate or severe endometriosis may have the best odds for getting pregnant through IVF — an assisted reproductive technology (ART) procedure where a previously retrieved egg (the same process that starts egg freezing) is fertilized in a lab and transferred into the uterus. If egg quality or quantity is low, fertility specialists may recommend using donor eggs.

If someone with endometriosis wants to have biological children but not for a while, specialists may advise preserving current fertility by freezing eggs, embryos, or ovarian tissue before surgery.

Think you might have endometriosis? Here are some resources

If you're wondering if you could have endometriosis but aren't sure enough to seek out a specialist, you can always join online communities to learn more about people's experiences with the condition:

This article was medically reviewed by Dr. Antonio Gargiulo, MD, a reproductive endocrinologist and minimally invasive gynecologic surgeon at Brigham and Women's Hospital and Harvard Medical School who specializes in treating endometriosis and other conditions associated with pelvic pain.


If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.

How we reviewed this article

Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

Current version

December 27, 2021

Written by

Sarah duRivage-Jacobs

Fact checked by

Antonio Gargiulo, MD

About the medical reviewer