Women with endometriosis were 46% more likely to develop type 2 diabetes than women without it, according to a study published in Diabetologia in August 2026.
The extra risk held even after researchers accounted for body weight, meaning it was not simply explained by obesity.
The analysis was led by researchers at George Mason University and drew on records from nearly 3 million people in the Utah Population Database.
About 100,000 had been diagnosed with endometriosis. The team tracked who went on to develop type 2 diabetes over an average follow-up of 10.8 years.
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Endometriosis is a condition in which tissue similar to the lining of the uterus grows outside it, often causing pelvic pain and sometimes infertility.
The World Health Organization estimates it affects around 10% of women and girls of reproductive age, roughly 190 million people worldwide.
The risk was highest in groups usually thought low-risk
The link was strongest in premenopausal women and in women whose body mass index was under 30, according to the George Mason team.
These are not the groups doctors typically flag as high-risk for type 2 diabetes, which makes the pattern harder to explain by weight or age alone.
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Risk also varied by the type and location of endometriosis. Women with extra-pelvic endometriosis, where the tissue grows outside the pelvis, faced the highest relative risk of any subtype.
Why the link may exist
Researchers point to chronic inflammation as a likely driver. Endometriosis involves persistent inflammatory activity in the body, and that ongoing inflammation can interfere with how insulin works.
When cells stop responding well to insulin, a state called insulin resistance, blood sugar starts to climb. Insulin resistance is a core step on the road to type 2 diabetes.
"Our findings add to a growing understanding that endometriosis may affect more than reproductive health alone," lead author Maggie Fuzak Nunziato, a doctoral student in epidemiology at George Mason, said in a statement.
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The study is observational, so it cannot prove that endometriosis causes type 2 diabetes. It shows the two travel together in a very large group of women.
What women with endometriosis can do
The authors did not call for routine diabetes screening in every woman with endometriosis.
They suggested that earlier attention to blood sugar and diabetes prevention could benefit this group, especially those with other risk factors such as a family history of diabetes, previous gestational diabetes, or polycystic ovary syndrome.
Women who have been diagnosed with endometriosis can raise the finding with their doctor and ask whether a fasting blood sugar test or an HbA1c is worth adding to routine bloodwork.
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HbA1c is a test that shows average blood sugar over the past two to three months.
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This article is made and published by Mie Hermansen, who may have used AI in the preparation.