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Diagnosing Endometriosis

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

During a 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, the outer walls of the uterus, and the 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. Infertility may also develop in people with mild endometriosis because inflammation can interfere with fertilization and implantation.

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 associated with a higher risk. Endometriosis generally improves in menopause, when menstruation ends.


NYU Langone doctors understand that the symptoms of endometriosis can interfere with your quality of life. Although some people 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.

The three common medical symptoms of endometriosis are called the three Ds: dysmenorrhea, dyspareunia, and dyschezia.

Dysmenorrhea is the symptom of painful periods. Some people experience sharp or crampy pain or both during menstruation, and it can cause them to miss school or work. This pain can be localized to the midline, or the right, left, or lower pelvis.

Dyspareunia is the symptom of painful intercourse, and this can negatively impact relationships with partners. For some people, the pain is so severe that they avoid intercourse altogether.

Dyschezia is the symptom of painful bowel movements. Some people only experience dyschezia during menstruation. Others experience dyschezia throughout their cycle, but it gets worse during menstruation.

The three Ds are not present in everyone with endometriosis, but most patients with endometriosis have painful periods at some point in their lives. Those on hormonal suppression may still experience endometriosis symptoms, despite not having periods.

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 related condition 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 focal tenderness, or pain that arises when pressure is applied to specific areas by touch (palpation). Most people with endometriosis only have focal tenderness when being examined.

During a pelvic exam, your doctor also checks for hardening of tissue in the pelvic area. A nut-like hard texture, or nodularity, can be a sign of endometriosis that has deeply infiltrated tissues outside of the uterus. This is also known as deep infiltrating endometriosis and is a severe form of the condition. Your doctor also checks for 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 clumps of tissue and cysts that are signs of endometriosis. 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 refined using MRI to help with surgical planning for endometriosis. This test uses a magnetic field and radio waves to create images of internal organs, allowing doctors to identify endometrial implants.

Patients who are most likely to benefit from this type of imaging include those who may have endometriosis of the ovaries, also known as endometrioma. Endometrioma is a sign of severe endometriosis, and patients are highly likely to have deep infiltrating endometriosis elsewhere in the pelvis such as the bladder or rectum. In addition, those who have nodularity on a pelvic exam may also benefit from an MRI, which provides detailed information on the extent of endometriosis.

If you have heavy periods, bleeding between periods, and severe menstrual cramps, your doctor might order an MRI to rule out adenomyosis, in which the endometrial lining grows into the muscular wall of the uterus.


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 take photos and look for endometriotic implants and adhesions to confirm a diagnosis of endometriosis. Your endometriosis surgeon systematically inspects the pelvis, recognizing the different ways that endometriosis appears in the body. If your surgeon finds endometriosis lesions, they are removed during the procedure. Then a pathologist examines the tissue to confirm the diagnosis.

Our Research and Education in Endometriosis

Learn more about our research and professional education opportunities.