Endometriosis is a chronic condition in which tissue similar to the endometrium, or uterine lining, grows outside of the uterus. During the menstrual cycle, endometrial tissue from the lining of the uterus sheds and grows back. However, sometimes endometrial tissue grows in parts of the body beyond the uterus, such as in other reproductive organs like the fallopian tubes or ovaries. In rare cases, endometriosis may extend further to the bladder, rectum, vagina, or even distant organs like the brain and lungs. These growths and related scar tissue, referred to as lesions, adhesions, nodules, or implants, are hallmarks of endometriosis.

Endometriosis has an impact on the reproductive health and quality of life of millions of girls and women of child-bearing age around the world. If you have endometriosis, read our fact sheet about this often misdiagnosed condition to stay in control of your health and well-being.

Prevalence and Incidence

• According to the World Health Organization (WHO), about 10 percent of girls and women are affected by endometriosis worldwide, which equates to approximately 190 million people.
• The U.S. Office on Women’s Health estimates that as many as 11 percent of women in the U.S. may be affected by endometriosis (over 6.5 million).
• African American and Hispanic women are diagnosed with the condition at a 40 percent lower rate than white women, when adjusting for health care access, according to a 2004 study.
• In women with chronic pelvic pain, the prevalence of endometriosis is about 45 percent.
• Researchers suspect that 30 percent to 50 percent of women with endometriosis experience infertility.
• The most common age range for an endometriosis diagnosis is 15 to 49.
• The diagnosis of endometriosis is often delayed by five to 10 years because many of the symptoms are nonspecific and overlap with other conditions.

Causes and Risk Factors

Health care experts theorize that endometriosis might stem from a process called retrograde menstruation. During this process, cells from the uterus travel up the fallopian tubes and implant in other places. About 90 percent of women experience retrograde menstruation. Still, only a small fraction (about 1 out of 10) end up with endometriosis, suggesting that additional immunologic, genetic, environmental, and biological factors also contribute to the condition.

Learn more about what else may cause endometriosis.

A woman with a mother or sister with endometriosis is more likely to develop the condition, according to research. Endometriosis has also been linked to other health conditions, including:

• Allergies
• Asthma
• Autoimmune diseases
• Breast cancer
• Chronic fatigue syndrome
• Fibromyalgia
• Ovarian cancer

Women have a higher likelihood of endometriosis when their menstrual cycle lasts 27 days or fewer, or if their periods last more than seven days, according to the Office on Women’s Health.

Endometriosis Symptoms

Endometrial tissue is very responsive to hormones, even when it’s not in the uterus. Endometriosis symptoms often fluctuate based on a person’s menstrual periods.

• In some cases, endometriosis is asymptomatic.
• The stage of endometriosis isn’t correlated with symptom severity. Mild cases can produce intense symptoms, and advanced cases can cause minimal symptoms.
• Researchers have found that endometriosis affects between 71 percent and 87 percent of women who experience chronic pelvic pain.
• Other common endometriosis symptoms include back and leg pain.
• Symptoms usually resolve or improve after menopause.

Other symptoms of active endometriosis include:

• Gastrointestinal issues (such as diarrhea or constipation)
• Low energy levels
• Intense menstrual cramps and painful periods
• Severe pain during sex, bowel movements, and urination
• Spotting between periods
• Trouble getting pregnant

Learn more about symptoms of endometriosis.

Endometriosis Treatment and Management

Some of the ways to manage endometriosis symptoms include:

• Undergoing acupuncture
• Practicing deep breathing
• Eating enough fiber and drinking water to prevent constipation
• Exercising to produce endorphins and promote blood flow
• Lying down to alleviate back pressure
• Taking over-the-counter pain relievers, like ibuprofen and acetaminophen
• Using a hot water bottle or heating pad for pelvic pain

Certain treatments for endometriosis have side effects that can affect future fertility. These treatments include medications (like birth control) that mimic the hormonal conditions of pregnancy or menopause. If you’d like to remain open to the possibility of pregnancy, be sure to discuss it with your health care provider.

Learn more about treatments for endometriosis.

Endometriosis and Fertility Outcomes

Endometriosis may reduce fertility through multiple effects, such as:

• Abnormal follicle development
• Chronic inflammation
• Disruption in the transport of the egg, sperm, or embryo
• Resistance to progesterone

Moreover, some studies show that women over 35 with endometriosis have double the rate of infertility compared to their counterparts of the same age.

Learn more about infertility and endometriosis.

Favorable Pregnancy Statistics

• Around 70 percent of women with mild to moderate endometriosis are able to become pregnant without treatment.
• Women with severe endometriosis (stages 3 and 4) have an excellent chance of getting pregnant with the right support.
• Overall, 75 percent of women with severe endometriosis can experience a healthy pregnancy, 66 percent of the time naturally and 33 percent of the time with in vitro fertilization (IVF).

If infertility becomes an issue, gynecologists may suggest laparoscopic surgery to remove the lesions. They may also offer assisted reproductive technology such as intrauterine insemination or IVF. For mild cases, treatment of endometriosis usually aims to remove most or all of the lesions, a procedure that typically improves fertility.

Laparoscopic removal of endometrial tissue has been shown to boost the chances of getting pregnant significantly:

• Individuals with an initial fertility rate of 2.4 percent saw the chance of conception increase to 30.7 percent within 36 weeks of the procedure.
• This improvement is similar to what’s expected from one round of IVF.

Pregnancy Complications

People living with endometriosis who want to become pregnant should work with their doctor and a fertility specialist to learn about the best treatment options to improve their chance of a safe and healthy pregnancy.

• Although more research is needed, there’s some evidence to suggest that endometriosis raises the risk of miscarriage by up to 20 percent.
• The risk of some complications, including placenta previa and ectopic pregnancy, may be slightly elevated with endometriosis, highlighting the importance of prenatal care.

Talk With Others Who Understand

MyEndometriosisTeam is the social network for people with endometriosis and their loved ones. On MyEndometriosisTeam, more than 125,000 members come together to ask questions, give advice, and share their stories with others who understand life with endometriosis.

Are you living with endometriosis? Share your story in the comments below, or start a conversation by posting on MyEndometriosisTeam.