Uterine fibroids (myomas or leiyomymas) are benign, monoclonal tumors of the smooth muscle cells found in the human uterus [1, 2]. Despite the fact that their cause is still unknown, yet there is considerable evidence that estrogens and progestogens proliferate tumor growth [3, 4], as the fibroids rarely appear before menarche  and regress after menopause . Uterine fibroids are the most common benign tumors in women and the leading indication for hysterectomies in the USA [7, 8], nevertheless, epidemiological data on fibroid prevalence and incidence are limited and reliable population-based research is lacking . Available data are difficult to compare due to differences in the study population and screening methods. Prevalence data range from 5% to 21% [10–13]. In a US study with randomly selected women between 35 to 49 years, who were screened by self-report, medical record and sonography, the incidence of uterine fibroids by age 35 was 60% among African-American women, increasing to > 80% by age 50, whereas Caucasian women showed an incidence of 40% by age 35, and almost 70% by age 50 . Apart from race, other possible risk factors for developing uterine fibroids are early age at menarche , familial predisposition  and overweight [17, 18]. Parity [15, 19–21] and smoking may protect from developing myomas [17, 19, 20, 22].
The majority of women with uterine fibroids are asymptomatic, consequently get less clinical attention and fibroid tumors often remain undiagnosed [23, 24]. Symptomatic women typically complain about abnormal uterine bleeding, specifically in terms of heavy and prolonged bleeding . In a study of Wegienka et al. (2004) women with myomas were more likely to report a "gushing"-type of bleeding and high pad/tampon use than women without myomas . Additionally, women with uterine fibroids may suffer more often from dyspareunia and non-cyclic pelvic pain . Although bleeding and pelvic pain symptoms are frequently reported in literature as main symptoms related to uterine fibroids, the number of systematic studies on fibroid symptoms is limited.
Therapeutic options to treat these symptoms include medical therapy, surgical interventions and uterine artery embolization . Medical treatments used to manage bleeding symptoms are oral contraceptives or progestins, although there is no evidence for their efficacy in treating myomas . Other medical alternatives are the Levonorgestrel-releasing intrauterine system (LNG-IUS) and GnRH-agonists. However, the LNG-IUS cannot be applied in case of significant distortion of the uterine cavity and the duration of treatment with GnRH-agonists is limited by the induction of hypoestrogenic symptoms. According to the reproductive desire of the patient and the severity of symptoms surgical procedures comprise myomectomy, endometrial ablation or hysterectomy.
In 2009 the Bayer Healthcare Pharmaceuticals initiated the Uterine Bleeding and Pain Women's Research Study (UBP-WRS), an internet-based-study across 8 countries. The objective of this large study was to gain patient-based prevalence data on uterine pain and bleeding indications and investigate uterine symptoms and women's treatment experiences. This article shows relevant results of the study for the indication uterine fibroids. According to our knowledge it is the largest international population-based study available on self-reported prevalence, symptomatology and management of uterine fibroids. It allows for cross country-comparison regarding prevalence data and management of uterine fibroids and reveals differences in symptomatology and risk factors in comparison with women without a diagnosis of uterine fibroids.