Endometriosis by the numbers
Learn about important facts and figures surrounding endometriosis.
Jan 18, 2026
Written byJameson Kowalczyk
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Slide 1
Endometrium, or endometrial lining, is a layer of specialized cells that make mucous that normally grows on the inside of the uterus. During a menstrual cycle, this layer of tissue grows and thickens. During menstruation, this layer is shed.
Endometriosis is a condition where endometrial-like tissue grows outside the uterus and attaches to other pelvic organs. These may include the ovaries, bladder, intestines, and inside the vagina. The condition can cause a range of symptoms, including inflammation, excess bleeding, and severe pain.
Here are some things to know about endometriosis, including how many people are affected, the average age of diagnosis, and how it might affect fertility.
Sources (9)
- Endometriosis Foundation of America. Endometriosis: Defining It, Recognizing It, and Treating It. Updated September 28, 2022.
- Endometriosis.org. Facts about endometriosis. Accessed October 8, 2024.
- Illinois Department of Public Health. Endometriosis. Accessed October 8, 2024.
- Mayo Clinic. Endometriosis. August 30, 2024.
- Office on Women’s Health. Endometriosis. Updated February 22, 2021.
- Laufer MR, Sanfilippo J, Rose G. Adolescent endometriosis: diagnosis and treatment approaches. J Pediatr Adolesc Gynecol. 2003 Jun;16(3 Suppl):S3-11.
- Marsh EE, Laufer MR. Endometriosis in premenarcheal girls who do not have an associated obstructive anomaly. Fertil Steril. 2005 Mar;83(3):758-60.
- Practice Committee of the American Society for Reproductive Medicine. Endometriosis and infertility: a committee opinion. Fertil Steril. 2012 Sep;98(3):591-8.
- The American College of Obstetricians and Gynecologists. Endometriosis. Reviewed June 2020.