Evidence quality 4.25/5
Eight-dimension review score against the quality rubric . Each dimension scored 1–5.
- D1 Source grounding
- 3/5
- D2 Source authority
- 4/5
- D3 Arithmetic
- 5/5
- D4 Uncertainty
- 4/5
- D5 Scope
- 5/5
- D6 Prose
- 5/5
- D7 Perception honesty
- 4/5
- D8 Caveat completeness
- 4/5
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≈ As likely as
Perceived
Endometriosis is simultaneously one of the most common gynecological conditions and one of the least intuitively understood in terms of its prevalence. Most adults cannot name a prevalence figure; those who can tend to significantly underestimate it. The condition's long diagnostic delay — averaging 7 to 11 years depending on the country — means that many women live with it for years before the word "endometriosis" ever appears in their medical record, which suppresses both public awareness and official prevalence figures. Surveys of women with endometriosis consistently report that they visited multiple providers before receiving a diagnosis, reinforcing a perception that the condition is rare when it is in fact common.
Rough estimate: Most adults have no clear prevalence estimate; those aware of the condition tend to guess lower than reality
Source: editorial intuition, not polled
Actual
~1 in 10 reproductive-age women worldwide
reproductive-age women, global
Show derivation
WHO estimates that endometriosis affects roughly 10% of reproductive-age women worldwide (~190 million). ACOG concurs with a ~1 in 10 figure for US women of reproductive age. A US National Survey of Family Growth (2011-2019) found a national self-reported prevalence of 6.4%, but this is widely considered an undercount because diagnosis requires either laparoscopy or advanced imaging, and many cases go undiagnosed for years. The true lifetime prevalence among women who live through their full reproductive years is likely closer to the 10% WHO figure, which is used here. Uncertainty band spans from the NSFG survey-based estimate (~0.06) to higher estimates from surgical series (~0.15) that include incidental findings in asymptomatic women undergoing surgery for other reasons.
Caveats: Endometriosis prevalence figures are inherently uncertain because definitive dia…
Endometriosis prevalence figures are inherently uncertain because definitive diagnosis historically required laparoscopic surgery, and many affected women never receive a diagnosis. The WHO/ACOG 10% figure is a consensus estimate that attempts to account for undiagnosed cases, but the true figure could be meaningfully higher or lower. The 7-11 year average diagnostic delay is one of the longest of any common medical condition, which means that point-in-time prevalence studies systematically undercount. This entry uses the prevalence figure (proportion of women who will have the condition at some point) rather than an annual incidence rate, because endometriosis is a chronic condition that does not have a clean "event per year" structure.
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Endometriosis affects roughly 1 in 10 women of reproductive age, according to both the World Health Organization (~190 million globally) and the American College of Obstetricians and Gynecologists. That makes it one of the most common gynecological conditions in the world — and one of the most consistently underestimated in casual conversation. The condition involves tissue similar to the uterine lining growing outside the uterus, causing chronic pain, heavy periods, and in many cases subfertility. A US National Survey of Family Growth (2011-2019) found a self-reported prevalence of 6.4%, but this is widely regarded as an undercount because diagnosis has historically required surgery, and many women live with symptoms for years before the word “endometriosis” ever enters their medical record.
The diagnostic delay is the defining structural problem. Across studies, the average time from symptom onset to diagnosis ranges from 7 to 11 years depending on the country. A 2023 Endometriosis UK survey of more than 4,300 people found that 47% had visited their GP 10 or more times, and 70% had visited 5 or more times, with symptoms before receiving a diagnosis. A 2025 systematic review and meta-analysis found the pooled average delay has gradually shortened over three decades of data — from roughly 9.8 years for studies published in 1990-2000 to about 5.6 years for 2011-2020 — but concluded that “even in the current century, with increased awareness of the disease and medical advancements, significant delays are observed,” with diagnosis times still ranging from 4.4 years to more than 10 years depending on the country. The reasons are partly clinical — symptoms overlap with irritable bowel syndrome, urinary tract infections, and “normal” menstrual pain — and partly cultural: menstrual pain has historically been normalized in clinical settings, and many women report being told their symptoms were psychological before eventually receiving a diagnosis.
Endometriosis is not evenly distributed across the population. Women with a first-degree relative who has the condition face roughly five to seven times the baseline risk. Prevalence among women presenting with subfertility reaches 50-70% in surgical series, though this partly reflects diagnostic selection bias (women who undergo surgery are more likely to have their endometriosis found). Early menarche and shorter menstrual cycles are associated with modestly higher risk, while multiparity and breastfeeding appear protective — consistent with the hypothesis that cumulative menstrual exposure matters. The honest summary: this is a common, underdiagnosed, and undertreated condition whose public profile is finally beginning to match its epidemiological footprint.
Related tidbits
Endometriosis affects roughly 1 in 10 reproductive-age women worldwide. Awareness lags the prevalence: most people can't name a figure, and those who can tend to guess low. Diagnosis is often delayed for years.
Claim ledger
Every number below is what each source reported, with the verbatim quote we relied on and how we arrived at our figure. Click any link to verify directly.
2/4 sources independently verified verbatim against the cited source
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[1] World Health Organization — Endometriosis — fact sheet
Endometriosis — fact sheet- Statistic
Endometriosis affects roughly 10% (190 million) of reproductive-age women and girls globally- Excerpt
“"Endometriosis affects roughly 10% (190 million) of reproductive age women and girls globally. [...] There is currently no known way to prevent endometriosis. Enhanced awareness, followed by early diagnosis and management, may slow or halt the natural progression of the disease." ”
- Source data from
- 2025-03-28
- Accessed
- 2026-04-24 · archived copy
- Calculation
- WHO gives the headline 10% figure directly. This is a prevalence estimate, not incidence, and covers women of reproductive age (~15-49). It is based on a synthesis of epidemiological studies and is the most widely cited global figure. The denominator is all reproductive-age women, not just those who have undergone diagnostic surgery, so it implicitly includes estimated undiagnosed cases.
- Independence
- WHO synthesises multiple epidemiological studies into a consensus prevalence figure. Methodologically distinct from the ACOG clinical guidance below, though both draw on overlapping literature.
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[2] American College of Obstetricians and Gynecologists — Endometriosis Verified
Endometriosis- Statistic
Endometriosis occurs in about 1 in 10 women of reproductive age- Excerpt
“"Endometriosis occurs in about 1 in 10 women of reproductive age. [...] Endometriosis is most often diagnosed in women in their 30s and 40s." ”
- Source data from
- 2024-12-01
- Accessed
- 2026-04-24 · archived copy
- Verification
- Excerpt independently re-fetched and confirmed word-for-word against the cited source during our grounding audit.
- Calculation
- ACOG's 1-in-10 figure aligns with the WHO consensus. ACOG notes that prevalence is much higher among women with subfertility or chronic pelvic pain, but the headline figure refers to the general population of reproductive-age women. Average diagnosis delay of 7-11 years means that cross-sectional prevalence studies undercount true lifetime prevalence.
- Independence
- ACOG is a US clinical-guidance body that synthesises peer-reviewed literature independently of WHO, though both draw on many of the same underlying studies.
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[3] Endometriosis UK — Years of being "dismissed, ignored and belittled": Endometriosis UK urges improvement to deteriorating diagnosis times
Years of being "dismissed, ignored and belittled": Endometriosis UK urges improvement to deteriorating diagnosis times- Statistic
In a 2023 survey of 4,371 people with endometriosis, 47% had visited their GP 10 or more times, and 70% had visited 5 or more times, with symptoms before receiving a diagnosis- Excerpt
“"Almost half of all respondents (47%) had visited their GP 10 or more times with symptoms prior to receiving a diagnosis, and 70% had visited 5 times or more." ”
- Source data from
- 2024-03-01
- Accessed
- 2026-07-03 · archived copy
- Calculation
- Endometriosis UK's own diagnosis-delay survey (N=4,371), published for Endometriosis Action Month 2024. This is a UK patient population, not a US one, but is used as evidence for the diagnostic-delay structural pattern described in the body prose, alongside the global WHO/ACOG prevalence figures. Not used for the entry's headline prevalence number.
- Independence
- Endometriosis UK is a patient charity conducting its own member/patient survey, independent of the WHO and ACOG prevalence syntheses above.
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[4] Frontiers in Medicine (Li, Feng & Ye, 2025) — Factors contributing to the delayed diagnosis of endometriosis — a systematic review and meta-analysis Verified
Factors contributing to the delayed diagnosis of endometriosis — a systematic review and meta-analysis- Statistic
Pooled mean diagnostic delay declined from approximately 9.8 years (1990-2000) to 5.6 years (2011-2020) across included studies, but reported diagnosis times still range from 4.4 to more than 10 years depending on country/region- Excerpt
“"even in the current century, with increased awareness of the disease and medical advancements, significant delays are observed, and diagnosis times vary between 4.4 years and more than 10 years." ”
- Source data from
- 2025-07-22
- Accessed
- 2026-07-03 · archived copy
- Verification
- Excerpt independently re-fetched and confirmed word-for-word against the cited source during our grounding audit.
- Calculation
- This meta-analysis pools mean diagnostic-delay figures across studies grouped into three periods (1990-2000, 2001-2010, 2011-2020), showing a downward trend (approx. 9.8 to 5.6 years) alongside continued substantial delay in absolute terms. Used in the body prose to support the claim that diagnostic delay remains a persistent structural problem even as it has gradually improved, replacing an earlier draft claim that delay was "not shrinking appreciably," which this source does not support (it documents gradual improvement) even though it does confirm delays remain multi-year in every region studied.
- Independence
- Independent peer-reviewed meta-analysis, methodologically distinct from the WHO/ACOG consensus prevalence figures and the Endometriosis UK patient survey above.