What is Endometriosis?

Endometriosis occurs when endometrial cells grow in areas outside of the endometrium, such as the ovaries, fallopian tubes, or other pelvic regions. This ectopic endometrial tissue promotes an inflammatory response that produces the clinical features of the disease. The condition likely occurs due to various factors such as abnormal immunity, alerted hormone signaling, and genetics.

Women are normally affected during their childbearing years and develop pain in the pelvic region, menstrual cramps (dysmenorrhea), and pain with sexual intercourse (dyspareunia). Other features include infertility and an ovarian mass, which is typically felt on physical examination. Individuals may experience gastrointestinal or urinary symptoms if ectopic endometrial tissue is next to the bladder or rectum.

The disorder is occasionally asymptomatic and found incidentally during imaging such as pelvic ultrasound. It is associated with a higher risk of pregnancy complications and certain ovarian cancers.

What Causes Endometriosis?

Endometriosis appears to be caused by multiple factors such as the implantation of endometrial tissue outside of the endometrium, immune dysfunction, abnormal hormonal signaling, and genetics.

Major risk factors for endometriosis include:

  • Nulliparity – having never given birth
  • Early menarche – first menstrual cycle
  • Late menopause
  • Shorter menstrual cycles

Women with multiple births, those who breast feed, and those with late menarche are at reduced risk of developing endometriosis.

How Common is Endometriosis?

Endometriosis is a common disorder that affects women and frequently requires referral to an obstetrics/gynecology specialist. The prevalence of the condition is approximately 1%-7%. It is seen in up to 50% of women with infertility and nearly 70% of women and adolescents who experience pelvic pain.

Signs and Symptoms

Women with endometriosis usually develop symptoms around age 25-35. Symptoms and signs most often include:

  • Pelvic pain
  • Dysmenorrhea
  • Dyspareunia
  • Infertility
  • Ovarian mass

Pain in the pelvic region is often manifested as menstrual cramps (dysmenorrhea) and pain with sexual intercourse (dyspareunia). Patients may also develop associated genitourinary or gastrointestinal symptoms due to deposition of endometrial tissue near the bladder and rectum, respectively. Occasionally, individuals have endometrial tissue in the diaphragm and pleural cavity, resulting is pulmonary symptoms such as chest pain or cough. Symptoms of endometriosis can be debilitating at times.

On physical examination, you doctor will perform an abdominal examination assessing for an adnexal (ovarian mass). A pelvic examination is also performed to evaluate for various features such as regional tenderness and nodules within the vagina.


The diagnosis of endometriosis is suggested based on symptoms, history, physical examination, and imaging studies. A definitive diagnosis requires histologic (microscopic) evaluation from a surgical biopsy. The diagnosis is often delayed by several years due to the nonspecific symptoms of endometriosis and risk of undergoing surgery.

Imaging tests such as abdominal ultrasound may reveal nodules in the ovaries, rectovaginal septum, and bladder wall. A definitive diagnosis requires a surgical biopsy, which is typically performed laparoscopically. Disease staging can also be performed during surgery. Biopsy is normally performed in individuals that are being considered for treatment with potentially harmful medications such as Danocrine (danazol). Surgical biopsy confirmation may not be necessary if low risk treatment with estrogen-progestin contraceptives is being considered.

Endometriosis Medication and Treatment

Endometriosis is a chronic disease that frequently requires lifelong management. Medical treatment of endometriosis may include the use of the following classes of medications:

  • Hormonal contraceptives
    • Progestin only
    • Combined estrogen-progestin
  • Gonadotropin-releasing hormone agonists
    • Synarel (nafarelin)
    • Lupron (leuprolide)
    • Suprefact (buserelin)
    • Danocrine (Danazol) – not commonly used due to androgenic side effects
  • Aromatase inhibitors – for severe, refractory endometriosis-related pain

The first-line treatment of the condition typically includes a combined estrogen and progestin contraceptive. These are well tolerated and generally affordable – they also provide additional benefits such as a reduced risk of ovarian and endometrial cancer. These agents come in a variety of forms including pills, transdermal patches, and vaginal rings. One example is  Mirena (levonorgestrel) an intrauterine device.

Patients with mild to moderate pelvic pain may benefit from the addition of a nonsteroidal anti-inflammatory drug (NSAID). Women with severe symptoms that are unresponsive to the aforementioned strategies often benefit from the use of gonadotropin-releasing hormone (GnRH) agonists. Those with refractory symptoms are frequently prescribed an aromatase inhibitor. Surgical resection of the ectopic endometrial tissue is typically the last resort.


  1. Practice Committee of the American Society for Reproductive Medicine. Treatment of pelvic pain associated with endometriosis: a committee opinion. Fertil Steril 2014; 101:927. - https://www.ncbi.nlm.nih.gov/pubmed/24630080
  2. Revised American Society for Reproductive Medicine classification of endometriosis: 1996. Fertil Steril 1997; 67:817. - https://www.ncbi.nlm.nih.gov/pubmed/9130884
  3. Duffy JM, Arambage K, Correa FJ, et al. Laparoscopic surgery for endometriosis. Cochrane Database Syst Rev 2014; :CD011031. - https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD011031.pub2/abstract

Endometriosis Medications

The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.