Endometriosis symptoms are similar to the symptoms of many other diseases. So any symptoms need to be investigated to confirm the diagnosis of endometriosis and to rule out other causes.

Possible causes of symptoms include:

• Painful periods that are simply caused by pain-producing prostaglandins and cramps (primary dysmenorrhea). Prostaglandins normally increase around the time of your menstrual period.
• Adenomyosis, a disease that occurs when the cells that normally line the uterus grow into the muscular tissue of the uterine wall.
• Noncancerous tumors in the wall of the uterus (uterine fibroids).
• Abnormal structure of the uterus.
• Excessive growth of the lining of the uterus (endometrial hyperplasia). This is caused by a hormonal imbalance.
• Noncancerous tumors growing out of the lining of the uterus (endometrial polyps).
• Reproductive organ cancers.

Other conditions that can cause pelvic pain in women include:

• Ovarian cysts.
• A mass outside of the uterus (adnexal mass).
• Sexually transmitted infections (STIs).
• Scar tissue in the pelvis (adhesions).
• Pelvic inflammatory disease (PID).
• A tubal-ovarian abscess.
• Physical or sexual abuse.
• Urinary tract problems.
• Bowel problems.