Endometriosis: A Review

Abstract

Importance: Endometriosis is a chronic, estrogen-dependent, inflammatory disease defined by endometrial-like tissue (lesions) outside the uterine lining. It affects up to 10% of women worldwide, and 9 million women in the US, during reproductive years.

Observations: Endometriosis has varying clinical presentations; however, 90% of people with endometriosis report pelvic pain, including dysmenorrhea, nonmenstrual pelvic pain, and dyspareunia, and 26% report infertility. Risk factors for endometriosis include younger age at menarche, shorter menstrual cycle length, lower body mass index, nulliparity, and congenital obstructive müllerian anomalies such as obstructed hemivagina. Although definitive diagnosis requires surgical visualization of lesions, a suspected clinical diagnosis can be made based on symptoms, supported by physical examination findings and imaging with transvaginal ultrasound and/or pelvic magnetic resonance imaging; normal physical examination and imaging do not exclude the diagnosis. The diagnosis is often delayed, averaging 5 to 12 years after onset of symptoms, with most women consulting 3 or more clinicians prior to diagnosis. Hormonal medications, such as combined oral contraceptives and progestin-only options, are first-line treatment and should be offered to symptomatic premenopausal women who do not currently desire pregnancy. In a network meta-analysis (n = 1680, 15 clinical trials), hormonal treatments including combined oral contraceptives, progestins, and gonadotropin-releasing hormone (GnRH) agonists led to clinically significant pain reduction compared with placebo, with mean differences ranging between 13.15 and 17.6 points (0-100 visual analog scale) with little difference in effectiveness among options. However, 11% to 19% of individuals with endometriosis have no pain reduction with hormonal medications and 25% to 34% experience recurrent pelvic pain within 12 months of discontinuing hormonal treatment. Surgical removal of lesions, usually with laparoscopy, should be considered if first-line hormonal therapies are ineffective or contraindicated. Second-line hormone therapies include GnRH agonists and antagonists, and third-line treatments include aromatase inhibitors. Hysterectomy with surgical removal of lesions may be considered when initial treatments are ineffective. However, approximately 25% of patients who undergo hysterectomy for endometriosis experience recurrent pelvic pain and 10% undergo additional surgery, such as lysis of adhesions, to treat pain.

Conclusions and relevance: Endometriosis is a common cause of pelvic pain affecting approximately 10% of reproductive-age women. Hormonal suppression with combined estrogen-progestin contraceptives or progestins is first-line treatment for women who are not seeking immediate pregnancy. Surgical removal of endometriosis lesions may be performed if hormonal therapies are ineffective or contraindicated, and hysterectomy may be considered if medical treatments and surgical removal of lesions do not relieve symptoms.