Endometriosis is a condition that causes the tissue that lines the uterus to grow somewhere else. These growths are called endometrial implants. The condition affects between 5%-18% of women in the United States. It is a common cause of infertility, and the leading cause of pelvic pain.

While implants are most commonly found on the ovaries, they can also grow on the:

  • Fallopian tubes
  • Outside of the uterus
  • Intestines
  • Appendix
  • Cervix
  • Bladder
  • Vagina

Rarely, endometrial implants can travel outside the pelvis to old surgery scars, the lungs, brain and liver.

Symptoms associated with endometriosis include:

  • Painful intercourse
  • Pelvic pain
  • Lower abdominal pain
  • Low back pain
  • Pain on urination
  • Pain on having bowel movements
  • Diarrhea or constipation
  • Rarely, chest pain or headaches

The cause of endometriosis is unknown, but retrograde menstruation—where menstrual blood flows back into the fallopian tubes instead of leaving the body—might contribute to it.