Diagnosing Endometriosis

Endometriosis happens when the tissue that lines the inside of a woman’s uterus, called the endometrium, grows outside the uterus. An estimated 6 percent to 10 percent of women of childbearing age have endometriosis.

During a woman’s menstrual cycle, the endometrium thickens to prepare for the possibility of pregnancy. If there is no pregnancy during that cycle, the endometrium exits the body during menstruation. In endometriosis, however, endometrial cells appear outside the uterus and attach to other organs and structures in the body, where they grow into nodules called “implants.” These implants, which have no way of leaving the body, swell and bleed as though they’re still inside the uterus. This causes surrounding tissue to become inflamed, resulting in pain and creating scar tissue called adhesions. 

Endometriosis often forms on the ovaries, outer walls of the uterus, and fallopian tubes as well as in a pocket of space behind the uterus called the cul-de-sac. It can also grow in the lower part of the large intestine, the bladder, and the rectum. Endometriosis can lead to infertility in several ways; for example, adhesions and endometrial implants can block the fallopian tubes, preventing sperm from fertilizing an egg. Endometriosis can also cause cysts called endometriomas to form on the ovaries, which can interfere with egg production and hormone functioning.  

The cause of endometriosis is unknown. Certain risk factors have been linked to it, such as the early onset of menstruation—at age 11 or younger—and a family history of the condition. Not having been pregnant is also linked with a higher risk. Endometriosis generally improves with menopause, when menstruation ends.


NYU Langone doctors understand that the symptoms of endometriosis can interfere with the quality of a woman’s life. Although some women experience no symptoms of endometriosis, others have pelvic pain before or during menstruation, with urination or bowel movements, and during sex. This pain can be severe or mild and does not necessarily correspond with the severity of endometriosis. Difficulty becoming pregnant can also be a sign of endometriosis. 

Diagnostic Tests

To diagnose endometriosis, your doctor assesses your health for other causes of pelvic pain, including: fibroids; interstitial cystitis, a painful bladder condition; pelvic organ prolapse; irritable bowel syndrome; pelvic inflammatory disease; pelvic floor muscle spasm; nerve-related pain; and adenomyosis, a condition related to endometriosis in which the endometrial lining grows into the muscular wall of the uterus.

Your doctor takes your medical history and performs one or more of the following exams and tests.

Pelvic Exam

Your doctor performs a physical exam and a pelvic exam to check for pain or tenderness, hardening of tissue in the pelvic area, endometrial implants, and scar tissue on or near the uterus. Adhesions caused by endometriosis can bind the uterus to nearby organs, making it immobile, so your doctor also checks for the mobility of your pelvic organs. 


If your doctor feels an abnormal mass during the pelvic exam, an ultrasound may be performed to check for fibroids or ovarian cysts, both of which are benign growths. Ultrasound uses sound waves to create images of the pelvic organs. This may be done using a handheld device called a transducer, which is placed on the abdomen, or by using a wand that fits into the vagina, which is used during a transvaginal ultrasound exam.

MRI Scans

NYU Langone doctors have recently refined techniques to identify endometriosis with the help of MRI. This test uses a magnetic field and radio waves to create images of internal organs, allowing doctors to identify endometrial implants. 

If you have heavy periods, bleeding between periods, and severe menstrual cramps, your doctor might order an MRI to rule out adenomyosis. 


Performed under general anesthesia, laparoscopy involves inserting thin instruments, including one with a light and camera at the tip, into small incisions in the abdomen. Your doctor uses the camera to look for endometrial implants and adhesions to confirm a diagnosis of endometriosis. Laparoscopy is also used to remove endometrial implants.

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