Endometriosis is a painful condition in which endometrium-like tissue grows outside the uterus in areas like the ovaries, abdomen, and bowel.

Diaphragmatic endometriosis occurs when this tissue grows into your diaphragm.

Your diaphragm is the dome-shaped muscle beneath your lungs that helps you breathe. When endometriosis involves the diaphragm, it usually affects the right side.

When endometrium-like tissue builds up within the diaphragm, it reacts to the hormones of your menstrual cycle, just as it does in your uterus. Women with diaphragmatic endometriosis almost always have endometriosis in their pelvis, too.

Diaphragmatic endometriosis is much less common than other forms of the condition, which typically affect the ovaries and other pelvic organs. This diaphragmatic type makes up only about 1.5 percent of all endometriosis cases.

Diaphragmatic endometriosis may not cause any symptoms. But you might experience pain in these areas:

  • chest
  • upper abdomen
  • right shoulder
  • arm

This pain usually occurs around the time of your period. It can be intense, and it may get worse when you breathe or cough. In rare cases, it can lead to a collapsed lung.

If endometriosis is in parts of your pelvis, you could also have symptoms like:

  • pain and cramps before and during your periods
  • pain during sex
  • heavy bleeding during or in between periods
  • fatigue
  • nausea
  • diarrhea
  • difficulty getting pregnant

Doctors don’t know exactly what causes diaphragmatic or other types of endometriosis. The most accepted theory is retrograde menstruation. However, it may not be the only cause — there could be multiple factors.

During menstrual periods, blood can flow backward through the fallopian tubes and into the pelvis. Those cells can then travel throughout the abdomen and pelvis and up into the diaphragm.

However, research has shown that most women experience retrograde menstruation, and yet most women don’t develop endometriosis. Therefore, it’s suspected that the immune system plays a role.

Other possible contributors to endometriosis likely include:

  • Cell transformation. Cells affected by endometriosis respond differently to hormones and other chemical factors.
  • Genetics. Endometriosis has been shown to run in families.
  • Inflammation. Certain substances that have a role in inflammation are found in high numbers in endometriosis.
  • Fetal development. These cells might grow in various places since before birth.

Diaphragmatic endometriosis may not cause symptoms. Even if you do have symptoms, you might mistake them for something else — like a pulled muscle.

Because this condition is so rare, your doctor may not recognize the symptoms either. One important clue to watch for: The symptoms of this condition are typically worse around your period.

Sometimes doctors discover endometriosis while doing surgery to diagnose another condition.

If you’re experiencing symptoms or suspect that you may be affected by endometriosis, talk with your doctor about the best steps towards diagnosis.

Often the best way to diagnose diaphragmatic endometriosis is with laparoscopy. This involves your surgeon making a few small cuts in your abdomen.

A scope with a camera on one end is inserted to help your doctor see your diaphragm and find the tissue. Small samples of tissue, called biopsies, are usually collected and sent to the lab so they can be examined under a microscope.

Once your doctor identifies endometrium-like tissue, they’ll make a diagnosis based on the location, size, and amount of this tissue.

Below is the most commonly used staging system for endometriosis, established by the American Society of Reproductive Medicine. However, these stages aren’t based on symptoms. Symptoms can be significant even with stage 1 or stage 2 disease.

They include:

  • Stage 1: Minimal — small patches in the pelvis, limited areas, and organs
  • Stage 2: Mild — more areas in the pelvis than stage 1, but with minimal scarring
  • Stage 3: Moderate — organs of the pelvis and abdomen are affected with scarring
  • Stage 4: Severe — widespread lesions affecting organ appearance with scarring

Scientists are currently working to establish other methods for describing endometriosis, especially in cases where deeper tissues are involved. The newer system is still in development.

If you don’t have symptoms, your doctor might recommend that you wait to treat your endometriosis. Your doctor will check you regularly to see whether symptoms develop.

If you do have symptoms, your doctor will likely recommend a combination of surgery and medication to help manage any symptoms you may have.


Surgery is the main treatment for diaphragmatic endometriosis. It can be done in a few different ways:

  • Laparotomy. In this procedure, your surgeon makes a large incision through the wall of the upper abdomen and then removes parts of the diaphragm affected by endometriosis. In one small study, this treatment reduced symptoms in all women and completely relieved chest and shoulder pain in seven out of eight women.
  • Thoracoscopy. For this procedure, your surgeon inserts a flexible scope and small instruments through small incisions in the chest to view and possibly remove areas of endometriosis within the diaphragm.
  • Laparoscopy. In this procedure, your surgeon inserts a flexible scope and small instruments into the abdomen to remove areas of endometriosis within the abdomen and pelvis.

Your surgeon can also use a laser to treat tissue affected by endometriosis. Surgery may also be necessary to manage scar tissue formation, a common complication in endometriosis.

If the endometriosis is in both your diaphragm and pelvis, you might need more than one surgery.

New treatment approaches are continually becoming available. Talk with your doctor about potential new treatments.


Two types of medications are currently used to treat endometriosis: hormones and pain relievers.

Hormone therapy can slow the growth of endometrium-like tissue and lower its activity outside of the uterus. Hormonal treatments include:

  • birth control, including pills, patch, or ring
  • gonadotropin-releasing hormone (GnRH) agonists or antagonists
  • danazol (Danocrine), now less commonly used
  • progestin injections (Depo-Provera)

Your doctor may also recommend over-the-counter (OTC) or prescription nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (Advil) or naproxen (Aleve), to manage pain.

Rarely, endometriosis of the diaphragm can cause holes to form in the diaphragm.

This can lead to life threatening complications, such as:

  • collapsed lung (pneumothorax) during your period
  • endometriosis in the chest wall or lungs
  • air and blood in the chest cavity

Having surgery to remove endometriosis within the diaphragm may reduce your risk for these complications.

Endometriosis of your diaphragm shouldn’t affect your fertility. But many people with this form of endometriosis also have it in their ovaries and other pelvic organs, which can cause fertility problems.

Up to 50 percent of people with endometriosis experience difficulties getting pregnant. Surgery and in vitro fertilization can increase your odds of getting pregnant.

Your outlook depends on how severe your endometriosis is and how it’s treated.

This type of endometriosis may not cause symptoms. If it’s painful or causes complications, you can have surgery to remove the tissue.

Endometriosis is a chronic condition, and it can have a big impact on your day-to-day life. To find support in your area, visit the Endometriosis Foundation of America or the Endometriosis Association.