Endometrial hyperplasia is relatively uncommon in the general population, with peak incidence rates ranging from about 56 to 213 per 100,000 women per year depending on the type. That said, the condition is significantly more common in certain groups, particularly women with obesity, polycystic ovary syndrome (PCOS), or those in their 50s and 60s. Because many cases go undiagnosed, these numbers likely underestimate the true frequency.
Incidence by Type and Age
Not all endometrial hyperplasia carries the same risk, and the different types occur at different rates. Simple hyperplasia (an even overgrowth of the uterine lining) peaks at about 142 per 100,000 women per year, while complex hyperplasia (a more irregular pattern of overgrowth) is slightly more common at 213 per 100,000. Both of these types peak in women in their early 50s, around the time of menopause, when hormone fluctuations are most dramatic.
Atypical hyperplasia, the type that carries the highest cancer risk, is less common at 56 per 100,000 women per year. It peaks about a decade later, in the early 60s. This distinction matters because the type you have largely determines what happens next in terms of monitoring and treatment.
Who Is Most at Risk
Certain factors push the odds much higher than those population-wide averages suggest. The core issue is prolonged exposure to estrogen without enough progesterone to balance it. Anything that creates that hormonal imbalance raises the risk.
PCOS is one of the strongest risk factors. In one study of women with PCOS who underwent uterine lining evaluation, 30% had hyperplasia. That’s a striking number compared to the general population rates. PCOS affects roughly 5% to 10% of reproductive-age women, and the chronic lack of ovulation it causes means the uterine lining gets stimulated by estrogen month after month without the progesterone that normally follows ovulation.
Obesity plays a compounding role. In the same study, women with hyperplasia had an average BMI significantly higher than those without it (roughly 45 versus 37). Fat tissue produces its own estrogen, so carrying more weight means a higher baseline estrogen level stimulating the uterine lining year-round. Other risk factors include taking estrogen-only hormone therapy without progesterone, irregular or absent periods for any reason, and diabetes.
Are Rates Rising or Falling?
Despite rising obesity rates, the overall incidence of diagnosed endometrial hyperplasia actually declined in recent years. A UK population study tracking cases from 2008 to 2020 found a 28.5% drop in incidence, falling from about 37.5 per 100,000 women to 26.8 per 100,000. Part of this reflects fewer biopsies being performed, but even after accounting for reduced sampling rates, there was still an 18.8% decline in diagnoses per 100 biopsies.
Researchers believe evolving diagnostic standards and greater pathology specialization have played a role. As pathologists have become more precise about what counts as true hyperplasia versus normal variations, some cases that would have been labeled hyperplasia in earlier years may now be classified differently. The numbers dropped further in 2020 (to 17 per 100,000), but that likely reflects pandemic-related disruptions in healthcare access rather than a real decline.
What It Feels Like
The most common sign is abnormal uterine bleeding. For premenopausal women, that typically means periods that are heavier or last longer than usual, or cycles shorter than 21 days. For postmenopausal women, any bleeding at all is the red flag. Some women have no symptoms, and the condition is discovered incidentally during evaluation for something else.
How It’s Diagnosed
Transvaginal ultrasound is usually the first step. In postmenopausal women with bleeding, a uterine lining thickness of 4 mm or less has a greater than 99% negative predictive value for cancer, meaning it’s very unlikely that anything serious is being missed at that thickness. When the lining measures thicker than 4 mm, or when the lining can’t be clearly visualized on ultrasound, a tissue sample is needed.
Even with a thin lining on ultrasound, bleeding that keeps coming back warrants a biopsy. Rare types of uterine cancer can develop with a lining as thin as 3 mm. If an initial biopsy comes back normal but bleeding persists, further evaluation with a camera-guided procedure and tissue sampling is the next step.
Risk of Progressing to Cancer
This is the question most people are really asking when they look up endometrial hyperplasia. The answer depends almost entirely on whether atypical cells are present.
Hyperplasia without atypia (simple or complex) has a long-term cancer progression risk of less than 5%. That’s reassuring, though it still calls for monitoring and, in most cases, hormonal treatment to reverse the overgrowth. Atypical hyperplasia is a different situation: roughly 30% of cases will progress to endometrial cancer over time. Some studies have found that a significant number of women diagnosed with atypical hyperplasia on biopsy already have undetected cancer when a more thorough tissue sample is examined, which is why treatment tends to be more aggressive.
How It’s Treated
For hyperplasia without atypia, the standard approach is progesterone therapy to counteract the estrogen overstimulation and encourage the lining to return to normal. A hormone-releasing IUD tends to produce higher regression rates than oral progesterone pills, and continuous oral therapy works better than cyclical dosing (taking the medication only part of the month). Follow-up biopsies are done to confirm the lining has normalized.
For atypical hyperplasia, hysterectomy is often recommended because of the significant cancer risk. Women who want to preserve their fertility may be offered hormonal therapy with close surveillance instead, but this path requires regular biopsies and a clear understanding that the risk of progression is substantial. The decision is highly individual and depends on age, fertility goals, and how the tissue responds to treatment over time.