How Endometriosis May Cause Infertility

Understanding Symptoms, Diagnosis, and Treatment

illustration of ovary
Ovary. MediaForMedical/UIG/Getty Images

Endometriosis is a condition where endometrium-like tissue forms and grows outside the uterus. Normally, endometrial tissue should only line the uterus and not grow anywhere else.

When endometrial tissue appears outside of the uterus, it may lead to pain and infertility.

Up to 50 percent of women who have endometriosis may experience infertility.

What Should Happen to Endometrial Tissue and What Happens Instead?

The endometrium is the inner lining of the uterus.

Throughout a woman's cycle, the lining thickens to prepare for an embryo. If pregnancy doesn't occur, the extra lining breaks down and is shed during menstruation.

With endometriosis, endometrial tissue exists not only inside the uterus but also in other areas of the body, where it does not belong. These are endometrial deposits or growths.

These endometrial growths usually form in the pelvic region, including on or near the ovaries. They can also appear less commonly near the rectum, vagina, fallopian tubes, or even in the urinary or gastrointestinal tracts.

More rarely, they can form far away from the pelvic area, including in the lungs, arms, or thighs.

In sync with your menstrual cycle, these deposits also thicken, break down, and bleed. The lost endometrial cells respond to your body's hormones the same way they would inside the uterus. 

Except unlike endometrium tissue that grows in the uterus, this tissue can't be expelled vaginally.

Instead, the endometrial deposits build up over time and form patches, scar tissue, cysts, and adhesions

What Are the Symptoms and Risks Factors for Endometriosis?

Not all women with endometriosis will have the same symptoms. In fact, it's possible to have few to no symptoms. This is one reason why endometriosis is difficult to diagnose.


Some potential endometriosis symptoms include:

Women who experience no obvious symptoms may only discover the endometriosis after an infertility evaluation. If you have a family history of endometriosis, you are also more likely to have the disease.

What Causes Endometriosis? 

Doctors aren't clear on what causes endometriosis, but there are theories. 

Menstrual back-flow: one theory is that menstrual blood occasionally back-flows from the uterus and through the fallopian tubes. These lost endometrial cells find themselves in the wrong parts of the body, causing problems. 

Doctors believe that most women experience menstrual back-flow, but women with endometriosis may have a malfunctioning immune system that doesn't react to the lost endometrial cells properly. 

Congenital birth defect: This theory is that endometrial tissue grew outside the uterus before the baby girl fetus was even born.

In other words, the tendency to have endometrium growing in the wrong places took place way before menstruation began. 

Eventually, when that girl grows up and starts menstruating, these deposits become a problem.  

Genetic cause: This theory is that endometriosis is a genetic issue. 

If your mother or sister has endometriosis, your risk of having the disease is significantly higher. 

How Does Endometriosis Cause Infertility?

Endometriosis is thought to be involved in 30 percent of infertility cases. Between 30 to 50 percent of women with endometriosis experience infertility.

Not every woman with endometriosis will have trouble conceiving.

In fact, pregnancy can lessen symptoms and development of the disease temporarily.

The connection between infertility and endometriosis isn't completely understood. You might assume endometriosis causes infertility by blocking the fallopian tubes (with endometrial deposits). But it's not a simple connection.

Even when there's no obvious barrier to fertilization, and the number of implants are few or are not blocking the egg or sperm from meeting, infertility can still result.

That said, here are some of the ways endometriosis may affect fertility:

  • Endometrial growths, scar tissue, adhesions, or cysts that are around the ovaries may prevent an egg from entering the fallopian tubes.
  • Endometrial tissue, if in the ovary, may actually prevent ovulation from occurring.
  • Endometriosis may form inside the fallopian tubes, blocking passage inside the tubes and preventing the egg and sperm from meeting.
  • Some researchers say that whatever causes endometriosis may also cause infertility. (The cause of endometriosis is not known, but some suspect it's related to a problem with the body's immune system.)
  • According to some researchers, women with endometriosis have low levels of a certain substance that helps a fertilized embryo implant itself into the uterine lining.
  • Endometriosis can make sexual intercourse painful for some women, and this pain may be worse around the time of ovulation. Not having sexual intercourse during ovulation would definitely interfere with your ability to get pregnant.

How Is Endometriosis Diagnosed?

The only way to confirm a diagnosis of endometriosis is with diagnostic laparoscopic surgery

This is an outpatient procedure that involves making a small incision in the abdomen, through which the surgeon inserts a tube with a special camera and (if needed) small surgical instruments.

To diagnose endometriosis, the surgeon will look for visual evidence of endometrial growths. If found, a biopsy of the tissue may also be performed to confirm things. The doctor should also use the surgery to evaluate the severity of the endometriosis (known as staging).

In mild to moderate cases, the doctor may even treat the endometriosis during the diagnosis surgery.

While laparoscopic surgery is the only way to confirm endometriosis, your doctor may order other tests including ultrasound, MRI, or CT scan to investigate cysts or other reasons for pelvic pain or infertility.

It is very important to know that endometriosis can not be ruled out with an ultrasound or physical exam. If you have not had an exploratory laparoscopy, you can't really know if you have endo or not.

How Is Endometriosis Treated?

You can get pregnant with endometriosis. That said, when we talk about endometriosis treatment, we don't only mean fertility treatments. ​If you're experiencing pain, your doctor can offer treatment for this as well.

Endometriosis treatment will depend on:

  • the severity of the disease
  • if you're experiencing pain
  • your age
  • whether you want to get pregnant

Some treatments for endometriosis would lead to decreased fertility, which would not be an option if you're trying to conceive.

Some of the options for treatment if you're trying to conceive include:

  • Laparoscopic surgery to remove endometrial growths, scar tissue, and adhesions caused by the endometriosis. This is not a cure. Endometriosis may return later. However, some women will have increased fertility for up to nine months after surgery.
  • IVF treatment, sometimes performed after surgery to remove endometrial growths, but sometimes done without surgical treatment.
  • In mild to moderate cases, IUI treatment along with fertility drugs may be used.

The pain of endometriosis may be treated with over-the-counter pain medications, acupuncture, and lifestyle changes, such as regular exercise and diet changes. Surgery to remove endometrial growths is also an option in treating the pain of endometriosis.

If you do not want to get pregnant, treatment options may also include hormonal treatments (which stop ovulation and prevent pregnancy) or, in cases of severe endometriosis, hysterectomy.

Hysterectomy involves removing the uterus alone or sometimes along with the ovaries. It is considered a treatment of last resort. You can't get pregnant after a hysterectomy.

More importantly, a hysterectomy does not cure endometriosis. For example, if the endometrial deposits are not removed as well, you can still have pain. 


Endometriosis. A.D.A.M. Healthcare Center. 

Endometriosis: A Guide for Patients. American Society of Reproductive Medicine.

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