Can You Have Both PCOS (Now PMOS) and Endometriosis?

Most women who type this question have already been given one diagnosis and are quietly suspicious of it. You have PCOS — now formally renamed PMOS, after a Lancet consensus this May — and the file is closed. But the pain doesn't behave the way anyone described. It arrives on a schedule. It's worse than "cramps." Nobody seems curious about it.

The short answer is yes, both conditions can be present in the same person. The longer answer is more useful, and more honest: researchers do not currently agree on how often that happens, and the estimates you'll find range from "rarely" to "about a third." Two papers published in the last two years point in opposite directions, and one landed at the end of July.

One line of research says they're near-opposites

In 2021, two evolutionary biologists proposed that endometriosis and PMOS are what they called diametric disorders — opposite ends of the same developmental axis, with PMOS shaped by high prenatal testosterone and endometriosis by low. Under that model, having both should be unusual, because the same hormonal setting can't sit at both extremes.

That's a hypothesis, not a finding. It's a synthesis of existing evidence across endocrinology, physiology and epidemiology rather than a study with a result.

But large-scale data has pointed the same way. A nationwide Korean cohort of 157,662 women, published in 2024, compared the conditions that cluster around each diagnosis and concluded the two "rarely co-occur." The comorbidity profiles came out quite different: PMOS ran with metabolic disease — hyperlipidemia, type 2 diabetes, gastrointestinal problems, pregnancy complications. Endometriosis ran with pain, benign reproductive and digestive neoplasms, endometrial hyperplasia. Infertility was one of the few things significantly associated with both.

Worth holding lightly: that study reads insurance claims codes, and endometriosis is one of the most under-coded diagnoses in medicine. A condition that takes years to identify will look rarer in claims data than it is in bodies.

Another line says they overlap more than expected

A 2024 genetics paper went the other way. Pooling genome-wide data on endometriosis (N = 470,866) and PCOS (N = 210,870), the authors found a positive genetic correlation between the two and identified 12 shared risk loci, with the signal concentrated in uterine, endometrial and fallopian tube tissue. Their Mendelian randomization analysis suggested each condition may raise the risk of the other. That method infers direction from genetic variants rather than observing it, so "may" is doing real work in that sentence — but it is not the picture you'd expect from two disorders that sit at opposite poles.

Then, on July 31 this year, a paper titled Challenging prior assumptions did what its title says. Researchers reviewed 165 consecutive transvaginal ultrasound examinations at a specialist endometriosis clinic. Of the 103 patients found to have endometriosis, 35% also had polycystic ovarian morphology on the same scan. Deep endometriosis was somewhat less common among those with polycystic ovaries; the difference for superficial and ovarian endometriosis wasn't statistically significant.

One more detail from that paper is easy to skip and shouldn't be. Among the women with endometriosis, each additional year of age lowered the odds of also having polycystic ovaries by roughly 17% (OR 0.83 per year). Follicle counts fall with age in everyone. Some of what looks like overlap may be a function of who happened to be young enough to still show it.

Polycystic ovaries on a scan are not the same as PMOS

This distinction is doing most of the work behind the disagreement, and it's the one most articles skip.

Polycystic ovarian morphology means a specific imaging appearance — under the 2023 International Guideline, roughly 20 or more follicles measuring 2–9 mm, or an ovarian volume above 10 mL. PMOS is a pattern diagnosis that needs two of three features: signs of high androgens, irregular or absent ovulation, and polycystic ovaries on ultrasound or an elevated AMH. Ovaries that look polycystic on a screen, by themselves, are one of three criteria and are common in women who never meet the definition. We go through the whole panel in what your PCOS blood test numbers actually mean.

So the 35% figure describes an imaging overlap in women attending a specialist endometriosis clinic — a group selected for having severe symptoms — not the proportion of women with endometriosis who also have PMOS. The honest read is that nobody has a trustworthy co-occurrence number yet, and anyone quoting you a clean single percentage is quoting past the evidence.

The real risk isn't having both. It's that one diagnosis explains away the other

This is the part that matters for the woman actually asking the question.

Endometriosis is already slow to identify. A 2025 systematic review in BJOG found reported times to diagnosis spanning 0.3 to 12 years depending on how the interval was defined and where patients lived, and concluded the delay is driven primarily by physicians rather than by patients. A separate 2025 meta-analysis found that provider-related factors — misdiagnosis and reliance on non-specific tests — carried a large pooled effect on how long diagnosis took.

Now add a PMOS diagnosis on the chart. It supplies a ready-made explanation for two of endometriosis's loudest symptoms: pelvic pain and trouble conceiving. Once a cause is on file, the search usually stops. The overlap problem, in practice, is less about biology than about what happens in a ten-minute appointment when there's already an answer in the notes.

The two conditions are also diagnosed by completely different routes. PMOS is identified from symptoms, bloodwork and imaging. Endometriosis is often only confirmed at laparoscopy — surgery nobody orders casually, and certainly not for a patient whose pain already has a label.

What to raise if the pain doesn't fit the PMOS story

We can't tell you whether you have endometriosis, and no article or online quiz can. What we can offer is the shape of the mismatch worth naming out loud at your next appointment.

PMOS's own signature is androgen excess, irregular or absent ovulation, and metabolic change — acne, unwanted hair growth, scalp thinning, cycles that skip. Severe cyclical pain is not one of its core features. It's worth asking specifically about endometriosis if:

• Pain reliably tracks your cycle and has been getting worse over years, rather than staying flat.
• You have pain during or after sex, or with bowel movements or urination.
• Your periods are heavy and painful — a pattern that fits endometriosis better than the infrequent, light or absent bleeding that's more typical of PMOS.
• You're being worked up for infertility and the anovulation story doesn't fully explain the findings.
• Pain is your dominant symptom while the androgen and metabolic side of PMOS is mild or absent.

None of these confirms anything. They're the details that make a clinician reach for a second explanation instead of reusing the first one, and being specific about them is the closest thing to leverage you have in a short consultation.

If you're still working out which parts of your own picture are driven by what, our free assessment maps which PMOS driver looks loudest in your answers — insulin resistance, androgens, ovulation, SHBG or cortisol. It takes no lab work and doesn't diagnose anything. For pain that behaves like the list above, the next step is a clinician who will treat it as its own question.

Sources

• Dinsdale NL, Crespi BJ. Endometriosis and polycystic ovary syndrome are diametric disorders. Evolutionary Applications. 2021 Jul;14(7):1693–1715. PMID: 34295358. — The diametric hypothesis: PMOS and endometriosis as opposite outcomes of prenatal testosterone exposure and HPG axis development. A synthesis and hypothesis paper, not a clinical study.
• Jeong HG, Jeon M, Ryu KJ, et al. Similar but Distinct Comorbidity Patterns Between Polycystic Ovary Syndrome and Endometriosis in Korean Women: A Nationwide Cohort Study. Journal of Korean Medical Science. 2024 Nov 18;39(44):e284. PMID: 39561807. — Insurance claims data on 157,662 women aged 15–45; the source for "rarely co-occur," the metabolic-versus-pain comorbidity split, and infertility as a shared association.
• Tan H, Long P, Xiao H. Dissecting the shared genetic architecture between endometriosis and polycystic ovary syndrome. Frontiers in Endocrinology. 2024;15:1359236. PMID: 38742190. — Genome-wide summary statistics (endometriosis N = 470,866; PCOS N = 210,870); positive genetic correlation, 12 shared pleiotropic loci, tissue enrichment in uterus, endometrium and fallopian tube, and bidirectional Mendelian randomization.
• Romeo P, Freger SM, Kalani N, et al. Challenging prior assumptions: coexistence of polycystic ovarian morphology and endometriosis on transvaginal ultrasound. Ultrasound in Obstetrics & Gynecology. 2026 Jul 31 (online ahead of print). PMID: 42536999. — Retrospective cohort of 165 patients at a tertiary gynecological ultrasound clinic; 35.0% (36/103) of those with endometriosis had concurrent polycystic ovarian morphology; age was inversely associated with concurrent PCOM (OR 0.83 per year, 95% CI 0.77–0.90).
• Teede HJ, Tay CT, Laven JJE, et al. Recommendations from the 2023 International Evidence-Based Guideline for the Assessment and Management of Polycystic Ovary Syndrome. Monash University; endorsed by ESHRE and ASRM, 2023. — The two-of-three diagnostic criteria and the ultrasound definition of polycystic ovarian morphology used here.
• De Corte P, Klinghardt M, von Stockum S, Heinemann K. Time to Diagnose Endometriosis: Current Status, Challenges and Regional Characteristics — A Systematic Literature Review. BJOG. 2025 Jan;132(2):118–130. PMID: 39373298. — Seventeen observational studies; reported diagnosis times of 0.3 to 12 years, with delay concluded to be primarily physician-driven.
• Li W, Feng H, Ye Q. Factors contributing to the delayed diagnosis of endometriosis — a systematic review and meta-analysis. Frontiers in Medicine. 2025 Jul 22;12:1576490. PMID: 40766070. — Pooled effect of provider-related factors, including misdiagnosis and reliance on non-specific diagnostics, on diagnostic delay (SMD 2.00, 95% CI 1.72–2.28).