Endometriosis: Symptoms, Causes and Treatment Options

Endometriosis is a long-term condition in which tissue like the lining of the uterus grows outside the uterus, most often on the ovaries and the lining of the pelvis. It affects about 1 in 10 women and girls of childbearing age. The main symptom is pelvic pain, especially painful periods that get worse over time. Period pain that keeps you from school, work or sleep deserves a doctor’s attention, and treatment can help.

Key points

Common symptoms are painful periods, pelvic pain, pain during sex and trouble getting pregnant.
Many people wait years for a diagnosis because the pain is brushed off as “normal” cramps.
An ultrasound or MRI can often find it. Keyhole surgery (laparoscopy) can confirm it and remove patches at the same time.
Hormone treatments and pain medicines control symptoms for many. Surgery helps when they don’t.
Endometriosis usually lasts until menopause, and symptoms often ease after that.

What happens in endometriosis

Each month, hormones make the lining of the uterus (the endometrium) thicken and then shed as a period. Patches of similar tissue outside the uterus also react to these hormones. They cause swelling and pain, and over time they can leave scar tissue (adhesions) that sticks organs together.

Patches are most often found on:

The ovaries, where they can form fluid-filled cysts (endometriomas, sometimes called chocolate cysts)
The fallopian tubes and the outside of the uterus
The lining of the pelvis, including the space behind the uterus
The bowel and bladder
Rarely, the diaphragm or lungs

Scarring can pull the uterus backward and hold it there. A tipped uterus (retroverted uterus) is common and usually normal, but one that is stuck in place can be a sign of endometriosis.

What causes endometriosis

No one knows for sure. Doctors think several things play a part:

Backward period flow. During a period, some blood flows back through the fallopian tubes into the pelvis. Most people have this, but in some the cells take hold and grow.
Genes. Endometriosis runs in families. Having a mother or sister with it raises your risk.
The immune system may fail to clear tissue that lands in the wrong place.
Hormones. Estrogen feeds the patches.

Starting periods young, having short cycles or long, heavy periods, and never having given birth also raise the risk.

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Endometriosis symptoms

Symptoms vary a lot. Some people with a few small patches have severe pain, while others with large patches have none.

Period cramps that are severe, start before bleeding begins, or get worse over the years
Pelvic or lower belly pain between periods, on one or both sides
Deep pain during or after sex
Pain with bowel movements or peeing, especially during a period
Heavy periods, or spotting between periods
Bloating, diarrhea, constipation or nausea, often worse around a period
Lower back or leg pain
Tiredness
Trouble getting pregnant

Endometriosis on the diaphragm or lungs is rare. It can cause chest or shoulder pain, coughing up blood, or a collapsed lung that happens around periods.

How endometriosis is diagnosed

Your doctor will ask about your pain and periods and do a pelvic exam. They may feel tender spots, cysts or a uterus that doesn’t move freely.

Transvaginal ultrasound. A slim probe placed in the vagina shows ovarian cysts and some deep patches.
MRI helps map deep disease on the bowel or bladder before surgery.
Laparoscopy. A surgeon looks inside the belly with a thin camera through a small cut near the belly button. They can take a sample and remove patches in the same operation.

A normal scan doesn’t rule out endometriosis, because small surface patches often don’t show up. Many doctors now start treatment based on symptoms and an exam, without waiting for surgery.

Endometriosis treatment

Pain relief

Anti-inflammatory pain medicines such as ibuprofen or naproxen help period pain. Heat, regular exercise and pelvic floor physical therapy help some people too.

Hormone treatment

These medicines calm the patches by lowering or steadying hormone levels. They control symptoms but don’t remove the tissue, so pain often returns when they stop.

Birth control pills, patch or ring, often taken without a monthly break
Progestin-only options, such as norethindrone or dienogest pills, an implant, a shot or a hormonal IUD
GnRH medicines, such as elagolix or relugolix pills or leuprolide shots. They lower estrogen a lot, which can cause hot flashes and bone thinning, so they are used for limited periods or with add-back hormones.

Surgery

Laparoscopy can cut out or burn away patches, free up scar tissue and remove ovarian cysts. It often eases pain, but endometriosis can come back. Removing the uterus (hysterectomy), sometimes with the ovaries, is an option for severe pain when you’re sure you don’t want more children. Even then, pain doesn’t always go away.

If you want to get pregnant

Many people with endometriosis get pregnant without help. If it’s taking a while, surgery, medicines that help with ovulation, or IVF can help. See a fertility specialist sooner rather than later, especially if you’re over 35.

Other causes of lower belly pain in women

Pain low on the right or left side can have many causes besides endometriosis, including ovarian cysts, appendicitis, pelvic infection, a urinary infection, kidney stones, fibroids, irritable bowel syndrome or a pregnancy outside the uterus (ectopic pregnancy).

Get emergency care for sudden, severe belly or pelvic pain, pain with fever or vomiting, fainting, or pain with a positive pregnancy test.

Common questions about endometriosis

How long does endometriosis last?

Endometriosis is a long-term condition that usually lasts until menopause. Symptoms often get better after menopause, when estrogen levels fall. Pregnancy can ease pain for a while. Treatment controls symptoms for many years, but there is no permanent cure yet.

Can endometriosis cause pain on the right side?

Yes. Endometriosis can cause pain on one side when patches or a cyst sit on the right or left ovary or pelvic wall. Pain on the lower right can also come from appendicitis, so see a doctor promptly for new or worsening one-sided pain.

Can endometriosis cause two periods in one month?

It can cause spotting or bleeding between periods that looks like a second period. Short cycles, hormonal birth control, fibroids, polyps, thyroid problems and early pregnancy can do the same. Bleeding between periods that keeps happening should be checked by a doctor.

Is endometriosis a type of cancer?

No. Endometriosis is not cancer and doesn’t spread the way cancer does. It slightly raises the risk of a few uncommon types of ovarian cancer, but the overall chance stays low. Your doctor will check any ovarian cysts that look unusual.