Endometrial Hyperplasia

By RRM Academy Reviewed by Dr. Naomi Whittaker, MD, Board-Certified OBGYN, MIGS, NFPMC, FCI Updated August 8, 2026

Endometrial hyperplasia is an overgrowth of the uterine lining caused by prolonged estrogen exposure without adequate progesterone to oppose it. The glands proliferate and crowd, producing abnormal uterine bleeding as the most common presenting symptom. Atypical hyperplasia (also called endometrial intraepithelial neoplasia, or EIN) is the direct pathologic precursor of endometrial adenocarcinoma. A long-term cohort followed untreated hyperplasia for a mean of 13.4 years. Cancer developed in 8% of women with simple atypical hyperplasia and 29% with the complex atypical subtype.¹ A national Gynecologic Oncology Group study measured concurrent cancer, disease already present in the surgical specimen at the time of hysterectomy. Among women who went straight to hysterectomy after a biopsy diagnosis of atypical hyperplasia, the specimen already contained invasive cancer 42.6% of the time.² The biopsy had missed it. Non-atypical hyperplasia carries substantially lower cancer risk and often resolves with hormonal correction.

The root cause is hormonal imbalance. Chronic anovulation, PCOS, obesity, exogenous estrogen without progesterone, and estrogen-secreting tumors are the common drivers. Cycle charting identifies anovulatory cycles and disrupted luteal phase patterns early, before hyperplasia is established. The hormonal context is visible in the chart before it becomes visible on biopsy.

Progesterone therapy reverses many cases of non-atypical hyperplasia by countering the unopposed estrogen state.³ For atypical hyperplasia in women who desire future fertility, intensive progestin therapy with close endometrial surveillance is a recognized option before hysterectomy. Either way, addressing the source of estrogen excess, not just treating the endometrium, is the restorative principle.

This content is for educational purposes only and does not constitute medical advice. Consult an RRM clinician or healthcare provider for guidance specific to your situation.