Female Pelvic Anatomy

What is adenomyosis?

Adenomyosis is a thickening of the uterus. The condition occurs when endometrial tissue moves into the uterus’ outer muscular walls. Normally, endometrial tissue lines the uterus. Adenomyosis may result in an adenomyoma, which is a mass or growth inside the uterus. Though the exact number of women affected is not known, some form of the condition may affect anywhere from 20% to 65% of women.

What causes adenomyosis?

The cause of this condition is not known. It is more common in women who have had multiple children (as opposed to those who have never had a child). It is not clear if adenomysosis is a separate medical condition, or represents a normal variant found in some women.

What are the symptoms of adenomyosis?

In many cases, there are no symptoms for the condition. Symptoms that may occur include:

  • Painful menstruation that may involve new cramping that becomes increasingly worse.
  • Heavy or prolonged menstrual bleeding.
  • A uterus that is 2-3 times its normal size.

Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy