What causes endometriosis? Penn State Health

What causes endometriosis?
Dr. Kristin Riley, Chief, Minimally Invasive Gynecologic Surgery

Endometriosis is a condition in which tissue that normally lines the uterus grows abnormally outside of the uterus. This tissue is made up of the same type of cells that line the inside of the uterus. These cells respond to hormones produced by your ovaries, which tell them to grow and then shed every month during your period. Because the abnormal tissue is made from this same type of cell, it also grows and sheds every month – only outside of the uterus – causing pelvic pain.

The cause of endometriosis is still being researched. One thought is that, when a woman with endometriosis has her period, the cells in the uterus travel backward through the fallopian tubes (the tubes that connect the uterus to the ovaries) into the pelvis. Researchers also believe the immune system plays a role in the condition.

Dr. Kristin Riley, Chief, Minimally Invasive Gynecologic Surgery