The endometrium is the innermost layer of cells within the uterus, this endometrial lining is where the oocyte from the ovary attaches to in order to begin a pregnancy.
Endometriosis occurs when endometrial cells grow in areas other than the inner uterus, such as the ovaries, fallopian tubes, or other pelvic regions. This endometrial tissue promotes an inflammatory response that leads to the signs and symptoms of the disease.
Women are normally affected during their childbearing years. Developing pain in the pelvic region, menstrual cramps (dysmenorrhea), and pain with sexual intercourse (dyspareunia). More severe complications 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 on imaging such as pelvic ultrasound or CT scan. It is associated with a higher risk of pregnancy complications and certain ovarian cancers.
Endometriosis is a complex disease that is thought to be caused by multiple factors. Genetics, the function of the immune system, the individual anatomy of the patient, and the natural hormone cycles of an individual all play a role in the risk of developing endometriosis.
Some of the major risk factors for endometriosis include:
- Nulliparity – having never given birth
- Early menarche – early first menstrual cycle
- Late menopause – beyond the age of 50
- Shorter menstrual cycles – Shorter than 4 days on average
Women with multiple births, those who breastfeed, and those with late menarche are at reduced risk of developing endometriosis.
Estimating the true prevalence of endometriosis is difficult as many individuals have extremely mild symptoms and do not seek medical care. Estimates of women in the United States living with endometriosis range from 1% to 7%.
Endometriosis is most commonly discovered in women who have issues with chronic pelvic pain or infertility. Endometriosis is seen in up to 50% of women with infertility and up to 70% of women between the ages of 13 and 40 who experience chronic pelvic pain.
Women with endometriosis usually develop symptoms around age 25-35. The most common symptom is increased discomfort during menstrual cycles. The other most common signs and symptoms include:
- Pelvic pain
- Ovarian mass
Pain in the pelvic region often presents as excessively painful menstrual cramps (dysmenorrhea) and pain with sexual intercourse (dyspareunia). Patients may also develop associated genitourinary or gastrointestinal symptoms due to the buildup of endometrial tissue near the bladder and rectum. Occasionally, individuals may have endometrial tissue in the diaphragm and pleural cavity, resulting in pulmonary symptoms such as chest pain or cough. These symptoms may be debilitating in individuals with more severe disease.
The diagnosis of endometriosis is often concealed by the normal changes in the body throughout puberty, the symptoms being closely associated with menstruation and the absence of any clear external signs.
The diagnosis is usually made after several doctor visits for abdominal pain, pelvic pain, and pain with intercourse. Imaging tests such as abdominal ultrasound may reveal nodules in the ovaries, rectovaginal septum, and bladder wall which may increase your physician’s suspicion for endometriosis. A definitive diagnosis requires a surgical biopsy which is generally done through minimally invasive surgery. Surgery is increasingly being skipped prior to beginning treatment due to the improvements in imaging technologies such as ultrasound.
A 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 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 – The first-line medications for endometriosis.
- Combined estrogen-progestin
- Gonadotropin-releasing hormone agonists – Have similar effects as hormonal contraceptives, but are more effective in some patients.
- Synarel (nafarelin)
- Lupron (leuprolide)
- Suprefact (buserelin)
- Danocrine (Danazol) – not commonly used due to androgenic side effects
- Aromatase inhibitors – for severe endometriosis-related symptoms that do not respond to the above medications.
- Arimidex (anastrozole)
- Femara (letrozole)
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 and prevention of unplanned pregnancy. These agents come in a variety of forms including pills, transdermal patches, and vaginal rings. One example is Mirena (levonorgestrel) an intrauterine device. Hormone based treatments always carry a mild risk of blood clots in the legs that can lead to pulmonary embolism. This risk can be increased by certain genetic and medical conditions and should be discussed with your physician.
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. These medications have an increased risk of side effects compared to more common medications and are generally only used after failing multiple other treatments. Surgical resection of the ectopic endometrial tissue is typically the last resort.
- 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
- Revised American Society for Reproductive Medicine classification of endometriosis: 1996. Fertil Steril 1997; 67:817. – https://www.ncbi.nlm.nih.gov/pubmed/9130884
- 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