What are Uterine Fibroids?
Uterine fibroids (leiomyomas) are common benign pelvic tumors that typically affect women of reproductive age. They are made up of smooth muscle cells located in the myometrium – the middle, muscular layer of the uterus. The nomenclature of urine fibroids is based on the location of the tumor in the uterus, such as intramural submucosal, intramural, and cervical.
Most cases of uterine fibroids are asymptomatic and detected incidentally on ultrasound. Women with large tumors may develop symptoms such as abnormal uterine bleeding, pelvic discomfort, and reproductive problems (infertility). Postmenopausal women with new or enlarging pelvic masses that result in pelvic pain and bleeding should be evaluated to exclude malignant neoplasms such as sarcoma. Due to the importance of this condition, it is critical that patients understand its causes, symptoms, and treatment.
What Causes Uterine Fibroids?
Uterine fibroids are benign smooth muscle tumors that are derived from cells of the middle, muscular layer of the uterus (myometrium). Theses tumors can be located in various layers of the uterus such as intramural, submucosal, subserosal, and cervical regions.
The precise cause of uterine fibroid development is unclear. These tumors likely occur due to a combination of factors such as genetic predisposition, environmental factors, steroid hormones, and growth factors important in fibrosis (scar formation) and angiogenesis (blood vessel formation).
How Common are Uterine Fibroids?
Uterine fibroids are the most common pelvic tumor in women. These tumors are often evaluated in the primary care clinic and may require referral to a gynecology specialist.
Most uterine fibroids shrink after menopause.
What are the Signs and Symptoms?
Symptoms and signs of uterine fibroids often include:
- Abnormal uterine bleeding – heavy or prolonged menstrual bleeding
- Pelvic discomfort – typically pain and pressure
- Reproductive abnormalities – infertility, complications during pregnancy or labor/delivery
Uterine fibroids are usually detected incidentally on pelvic imaging such as ultrasound or occasionally in women with symptoms. Abnormal uterine bleeding and pelvic cramps are the most common symptoms. Uterine fibroids can be single or multiple in number and vary in size from sub-centimeter tumors to lesions that are multiple centimeters in diameter. In most cases, tumors are small and asymptomatic. Large tumors often cause heavy menstrual bleeding, abdominal distension, and fullness. Your doctor will typically perform a pelvic examination, which may show an enlarged uterus with irregular contour.
How is it Diagnosed?
The diagnosis of uterine fibroids is suggested based on symptoms and physical examination, but typically confirmed with imaging studies. Your doctor will usually obtain a transvaginal ultrasound. Occasionally they will infuse the uterus with saline in order to better characterize the tumors on ultrasonography. Pathologic diagnosis with tissue biopsy is not typically necessary unless a malignant tumor is suspected such as uterine sarcoma.
If you have heavy or prolonged menstrual bleeding, you doctor will often obtain a CBC (complete blood cell count) to ensure you are not anemic. If you are a sexually active woman of childbearing age with abnormal uterine bleeding and pelvic cramps, pregnancy is always a consideration. Your doctor may order a urine pregnancy test.
How are Uterine Fibroids treated?
Most asymptomatic women with uterine fibroids are not treated. Women who are trying to get pregnant may benefit from surgery (hysteroscopic myomectomy) if they have resectable submucosal tumors. Similarly, tumors that are compressing important structures (e.g., urinary tract) may also require surgical removal despite the absence of symptoms.
Most postmenopausal women do not require treatment as uterine fibroids tend to become smaller and asymptomatic in this age group. However, postmenopausal women with new or enlarging pelvic masses that result in pelvic pain and bleeding should be evaluated to exclude malignant neoplasms such as sarcoma.
Symptomatic women with fibroids located in the submucosal layer of the uterus can benefit from minimally invasive surgery (hysteroscopic myomectomy). Tumors that are not amenable to hysteroscopic removal often require open resection (abdominal myomectomy). Abdominal myomectomy is also usually required for symptomatic intramural and subserosal uterine fibroids in women who wish to bear children. Depending on your hospital, other options may include laparoscopic myomectomy and uterine artery embolization.
Women who do not desire fertility may undergo definitive treatment with hysterectomy (surgical removal of the uterus).
Occasionally, your surgeon will recommend a medication to shrink the tumor prior to surgery. This may include a gonadotropin-releasing hormone agonist such as Synarel (Nafarelin) or Lupron (Leuprolide). Women with abnormal uterine bleeding may also benefit from a trial of hormonal contraceptive therapy with a Mirena (Levonorgestrel) intrauterine device.
- Alternatives to Hysterectomy in the Management of Leiomyomas. ACOG Practice Bulletin No. 96. American College of Obstetricians and Gynecologists. Obstet Gynecol 2008; 112: 201. - https://www.acog.org/clinical/clinical-guidance/practice-bulletin/articles/2008/08/alternatives-to-hysterectomy-in-the-management-of-leiomyomas
- Parker WH. Uterine myomas: management. Fertil Steril 2007; 88:255. - https://www.ncbi.nlm.nih.gov/pubmed/17658523
- Marret H, Fritel X, Ouldamer L, et al. Therapeutic management of uterine fibroid tumors: updated French guidelines. Eur J Obstet Gynecol Reprod Biol 2012; 165:156. - https://www.ncbi.nlm.nih.gov/pubmed/22939241
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.