How Common is Endometriosis?

In the United States alone, it has been estimated that nearly 6.5 million women have endometriosis. This is roughly 11% of women.1-3 However, researchers have suggested that this number may underestimate the true proportion of women who have the condition, as some women may have been misdiagnosed with another condition, are still awaiting diagnosis, or are asymptomatic. In the last case, women with endometriosis experience few to no symptoms of endometriosis, and may not seek treatment. These women may never be diagnosed, but may be living with the condition daily. It’s also hard to estimate the true proportion of women with endometriosis since formal diagnosis of the condition happens after surgical intervention, and not all women with symptoms of endometriosis will undergo surgery.

Who gets endometriosis?

The age group with the highest incidence of endometriosis has been slightly debated, however, most experts agree that women who are of reproductive age, roughly ages 25-40, are the most commonly affected by the condition.1,2 Despite this, endometriosis can be diagnosed at many points across the lifespan, including in adolescence through menopause, but diagnosis before puberty and post-menopause is rare. It has been estimated that nearly 70% of all women with endometriosis started experiencing symptoms before 20 years old.4 Some estimates suggest that roughly 20-40% of women with infertility and 70-90% of women with chronic pelvic pain receive a diagnosis of endometriosis.1 In female teenagers, it has been theorized that 20-40% of those who experience pelvic pain unrelated to their menstrual cycle receive a diagnosis of endometriosis.4 Additionally, endometriosis is found in roughly half of all teenagers with menstrual period pain severe enough to require a laparoscopy.4

The incidence and prevalence of endometriosis does not appear to be associated with race or ethnicity. This means that endometriosis does not appear to affect one race or ethnicity of women more than any other. Slight variations in the incidence of endometriosis in different racial or ethnic groups are often thought to be related to genetic or environmental-related risk factors, however, overall, a racial or ethnic bias has not been found for endometriosis.5

Possessing certain risk factors may increase a woman’s risk of developing or being diagnosed with endometriosis. Some of these risk factors include:

  • Low body mass index
  • Having your first period at an early age, such as before 11 years old (early menarche)
  • Having shorter menstrual cycles that last less than 28 days
  • Family history of endometriosis (having a mother, sister, grandmother, aunt, etc. who has endometriosis)
  • Prolonged periods (periods that last longer than a week)
  • Periods with very heavy menstrual flow
  • Never having a child (or not having a child yet)
  • Having a condition that affects normal menstrual blood flow out of the body, such as uterine fibroids
  • Abnormal development of the female reproductive system (also called müllerian anomalies)1,2,6

If you are concerned about your risk (or a loved one’s risk) of developing endometriosis, talk with your doctor or healthcare team about your specific situation. The risk of developing endometriosis may vary greatly from person to person, and be based on a variety of different factors.

Written by: Casey Hribar | Last reviewed: June 2018
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