Endometriosis is classically defined as the presence of endometrial glands and stroma in ectopic locations, primarily the pelvic peritoneum, ovaries, and rectovaginal septum. Affecting 6-10% of women of reproductive age, endometriosis is characterized by dysmenorrhea, dyspareunia, chronic pelvic pain, irregular uterine bleeding and/or infertility. The prevalence of this condition in women experiencing pain, infertility, or both is as high as 35-50%
According to the most convincing model, the retrograde menstruation hypothesis, endometrial fragments reaching the pelvis via trans tubal retrograde flow, implant onto the peritoneum and abdominal organs, proliferate and cause chronic inflammation with formation of adhesions. The number and amount of menstrual flows together with genetic and environmental factors determines the degree of phenotypic expression of the disease. Endometriosis is estrogen-dependent, manifests during reproductive years and is associated with pain and infertility. Dysmenorrhea, deep dyspareunia, dyschezia and dysuria are the most frequently reported symptoms.
Standard diagnosis is carried out by direct visualization and histologic examination of lesions. Pain can be treated by excising peritoneal implants, deep nodules and ovarian cysts, or inducing lesion suppression by abolishing ovulation and menstruation through hormonal manipulation with progestins, oral contraceptives and gonadotropin-releasing hormone agonists or antagonists. Medical therapy is symptomatic, not cytoreductive; surgery is associated with high recurrence rates. Although lesion eradication is considered a fertility-enhancing procedure, the benefit on reproductive performance is moderate. Assisted reproductive technologies constitute a valid alternative. Endometriosis is associated with a 50% increase in the risk of epithelial ovarian cancer.
As with all hormonal treatments, endometriosis symptoms return after women stop taking hormonal therapy such as GnRH agonists. These medications also have significant side effects because of estrogen deprivation, including hot flashes, tiredness, problems sleeping, headache, depression, joint and muscle stiffness, bone loss, and vaginal dryness.