The possible link between endometriosis and diabetes returned to the news on 14 August 2026, after a large American cohort study reported that women with endometriosis had a 46% higher risk of developing type 2 diabetes. The research, published in the journal Diabetologia, followed nearly 3 million women in Utah over 25 years. It does not prove that one condition causes the other, and an earlier European study found no such link at all. But it raises a practical question for anyone living with the condition: which blood tests are worth keeping an eye on? In this article you will learn what the study actually measured, why the evidence remains divided, and which markers doctors use to follow metabolic health over time.
What the new study reported
Researchers from George Mason University and the University of Utah assembled a population-based cohort of roughly 2.9 million people assigned female at birth, drawn from the Utah Population Database between 1996 and 2021. Close to 100,000 of them received a diagnosis of endometriosis during an average follow-up of almost 11 years. Compared with women who did not have the condition, they were 46% more likely to go on to be diagnosed with type 2 diabetes.
Three details make the finding more interesting than the headline number:
- The association was strongest for endometriosis located outside the pelvis, where the risk was roughly two and a half times higher.
- It was more pronounced before menopause than after it.
- It was more pronounced in women whose body mass index stayed below 30 — a group not usually considered at high risk of diabetes.
The authors are explicit that this is an association and not a demonstrated cause. They also flag a limitation worth remembering: women who are followed closely for one condition tend to be tested more often for others, which can inflate an apparent link.
Why the evidence is still divided
This is where careful reading matters. A French prospective study, the E3N cohort of almost 99,000 women, asked the same question and found no increase in type 2 diabetes risk among women with surgically confirmed endometriosis. Two large studies, two different answers.
The most likely explanation is methodological. The 2026 work separated endometriosis into clinical subtypes instead of treating it as a single condition. Earlier research pooled every form together, which can dilute a signal that exists only in certain subgroups. Other teams have pointed in a compatible direction, reporting a higher likelihood of metabolic syndrome and lower HDL cholesterol among women with the condition. Taken together, the picture is a plausible but unconfirmed metabolic signal — not a settled fact, and not a reason for alarm.
What inflammation has to do with blood sugar
Endometriosis is a chronic inflammatory condition. Inflammation that persists over years can make cells respond less efficiently to insulin, the hormone that moves glucose out of the bloodstream. When cells resist insulin, the pancreas compensates by producing more of it. Blood glucose can therefore look normal for a long time while insulin levels quietly climb, which is why a single reassuring glucose reading does not always tell the whole story. Our companion article explains insuliiniresistenssiä normaalipainoisilla henkilöillä.
Inflammation itself can also be measured. Doctors sometimes order C-reaktiivinen proteiini -testi, although a raised result has many possible explanations and never points to one disease on its own.
Which blood tests track metabolic health
None of the tests below diagnose endometriosis, and none of them are specific to it. They are the standard markers a doctor uses to see whether glucose metabolism is drifting. The table sets out what each one measures, with the reference points the CDC publishes for adults in the United States.
| Testata | Mitä se mittaa | CDC reference points |
|---|---|---|
| Fasting blood sugar | Glucose after an overnight fast | Normal 99 mg/dL or below; prediabetes 100–125; diabetes 126 or above |
| A1C | Keskimääräinen verensokeri viimeisten 2–3 kuukauden aikana | Normal below 5.7%; prediabetes 5.7–6.4%; diabetes 6.5% or above |
| Glucose tolerance test | Glucose 2 hours after a sugary drink | Normal 140 mg/dL or below; prediabetes 140–199; diabetes 200 or above |
| Fasting insulin and C-peptide | How much insulin the pancreas is producing | No single national threshold; always read alongside glucose |
| Lipidipaneeli | Kolesteroli ja triglyseridit | Interpreted with glucose to judge overall metabolic risk |
Each of these has its own reading rules. Our guides cover normal glucose ranges and what results mean, HbA1c-muunnostaulukko ja what a C-peptide result reveals about insulin. For the fuller picture, see the diabetes blood test panel, the lipid panel ja laajan aineenvaihduntapaneelin.
Milloin ottaa asia puheeksi lääkärin kanssa
The 2026 findings do not create a new screening rule, and no health authority currently recommends extra diabetes testing on the basis of endometriosis alone. What they do offer is a reasonable prompt for a conversation. It may be worth raising the subject if you have endometriosis and any of the following applies:
- You have never had a fasting glucose or A1C test as an adult.
- A previous result sat in the prediabetes range and was never rechecked.
- You had gestational diabetes during a pregnancy.
- A parent, sibling or child has type 2 diabetes.
- You notice increased thirst, more frequent urination, unexplained fatigue or slow-healing wounds.
Hormonal context matters too, because oestrogen influences both endometriosis and glucose handling. Our articles cover the female hormone panel ja what menopause changes about blood sugar. The reference guide covering endometriosis symptoms, diagnosis and treatment remains the starting point for the condition itself.
Uusimmat tieteelliset edistysaskeleet
Here is what recent research adds, in plain terms.
The Diabetologia study published in August 2026 is the largest of its kind so far. What it found: women with endometriosis were diagnosed with type 2 diabetes more often than women without it, and the gap was widest in groups usually seen as low risk. What this means for you: if you have endometriosis, a normal weight does not automatically place you outside the conversation about blood sugar. The result still needs confirming in other populations.
The French E3N cohort — a group of women followed over many years — reached the opposite conclusion, finding no excess risk. What this means for you: the science is genuinely unsettled, and any article claiming endometriosis causes diabetes is going further than the evidence allows.
Two further studies looked at metabolic syndrome, a cluster of findings that includes raised blood sugar, raised triglycerides and low HDL cholesterol. Both reported it more often in women with endometriosis, and one found low HDL to be about twice as common. What this means for you: if your doctor orders a lipid panel alongside a glucose test, that is a sensible pairing rather than an over-reaction.
None of this research changes treatment for endometriosis, and none of it describes a blood test that detects endometriosis. It simply supports keeping an eye on metabolic markers over time.
Sanasto
| Termi | Määritelmä |
|---|---|
| Endometrioosi | A condition in which tissue similar to the lining of the uterus grows outside the uterus, often causing pain and sometimes affecting fertility. |
| Kohorttitutkimus | A study that follows a defined group of people over time to see who develops a given condition. It can show links but cannot prove cause. |
| Insuliiniresistenssi | A state in which cells respond poorly to insulin, so the pancreas must produce more of it to keep blood sugar in range. |
| Prediabetes | Blood sugar higher than normal but below the diabetes threshold. It is often reversible with changes to diet and activity. |
| HbA1c (A1C) | Glycated haemoglobin, a blood marker reflecting average blood sugar over roughly the previous three months. |
| Metabolinen oireyhtymä | A cluster of findings including raised blood sugar, raised triglycerides, low HDL cholesterol, high blood pressure and increased waist size. |
| HDL-kolesteroli | Often called good cholesterol, it helps carry cholesterol away from the arteries. Low levels are linked to higher cardiovascular risk. |
| Premenopausal | Describing the years before menopause, when menstrual cycles and ovarian hormone production are still ongoing. |
Usein kysytyt kysymykset
Does endometriosis cause type 2 diabetes?
No study has shown that it does. The 2026 research found that the two occur together more often than expected, which is an association. Causation would require different study designs, and a large French cohort found no link at all. The honest summary is that a possible relationship is under investigation and remains unproven.
Should I ask for a diabetes test if I have endometriosis?
There is no official recommendation to screen for diabetes because of endometriosis. That said, a fasting glucose or A1C test is inexpensive, widely available and useful for most adults at some point. If you have other risk factors, or simply have never been tested, it is a reasonable thing to raise at your next appointment.
Can a blood test diagnose endometriosis?
Not currently. Diagnosis rests on symptoms, pelvic examination, imaging such as ultrasound or MRI, and in some cases laparoscopy. Blood markers may support the assessment of related conditions, but no routine blood test confirms or rules out endometriosis.
Why would a normal weight matter in this study?
Because it was unexpected. Type 2 diabetes risk usually rises with body mass index, so the strongest signal appearing in women below a BMI of 30 runs against the usual pattern. One hypothesis is chronic inflammation acting independently of weight, but this has not been demonstrated.
What is the difference between fasting glucose and A1C?
Fasting glucose captures a single moment after an overnight fast. A1C reflects an average across the previous two to three months and needs no fasting. Doctors often use both, because one can be normal while the other is not.
Does treating endometriosis lower diabetes risk?
There is no evidence either way. No trial has tested whether treating endometriosis changes metabolic outcomes, so any claim in that direction would be speculation.
Lähteet
- Centers for Disease Control and Prevention — Diabetes Testing, 2024 — cdc.gov
- Office on Women’s Health, US Department of Health and Human Services — Endometriosis, 2025 — womenshealth.gov
- Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) — About Endometriosis — nichd.nih.gov
- Fuzak Nunziato M, Yan B, Schliep KC, et al. — Endometriosis subtypes and risk of type 2 diabetes: the ARCHES retrospective cohort study — Diabetologia, 2026 — doi.org/10.1007/s00125-026-06828-w
- Vaduva P, et al. — Association between endometriosis and risk of type 2 diabetes: results from the prospective E3N cohort — Maturitas, 2023 — consensus.app
- Li BJ, et al. — Association between endometriosis and metabolic syndrome: a cross-sectional study based on NHANES data — Gynecological Endocrinology, 2023 — consensus.app
- Saei Ghare Naz M, et al. — Cardio-metabolic risk profile of women with endometriosis: a population-based study — Endocrinology, Diabetes & Metabolism, 2024 — consensus.app
Lisälukemista
- Verikokeen tulosten lukeminen
- Verikoetulokset selitetty – viitearvot ymmärrettävästi
- Diabetes symptoms, causes and treatment
- Low HDL cholesterol causes and risks
- What an online diabetes risk score really tells you
Ymmärrä laboratoriotuloksiasi tekoälyn DiagMen avulla
Living with endometriosis often means collecting a lot of test results over the years, without always knowing which numbers deserve attention. AI DiagMe reads your laboratory report and explains it in plain language, including markers such as fasting glucose, A1C, insulin and the lipid panel. It helps you understand what you are looking at and prepare better questions for your appointment. It does not make a diagnosis and does not replace your doctor.
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