Uterine Fibroids Part One

Leiomyomas are benign smooth muscle neoplasms that typically originate from the myometrium*
~They are often referred to as uterine myomas, and are incorrectly called fibroids because the considerable amount of collagen contained in many of them creates a fibrous consistency.
~Their incidence among women is generally cited as 20 to 25 percent, but has been shown to be as high as 70-80% in studies using histologic or sonographic examination.
~In many women, leiomyomas are clinically insignificant. Conversely, in some, their number, size or location within the uterus can provoke a myriad of symptoms.

Grossly, leiomyomas are round, pearly white, firm, rubbery tumors that on cut-surface display a whorled pattern

Uterine leiomyomas are estrogen- and progesterone-sensitive tumors. Consequently, they develop during the reproductive years and regress in size and incidence after menopause.

There are a number of conditions associated with increased estrogen production that encourage leiomyoma formation
---for example, the increased years of estrogen exposure found with early menarche*and with an increased body mass index (BMI) are each linked with a greater risk of leiomyomas.
---Obese women produce more estrogens due to increased production of estrogens in their fat tissue as well as a decreased ability of the liver to produce proteins that bind to sex hormones.

Because pregnancy is a progesterone- dominant state, it should provide an interlude from chronic estrogen exposure, and intuitively at least, should discourage leiomyoma development.
~In support of this, women giving birth at an early age, those with higher parity*, and those with a more recent pregnancy all display lower incidences of leiomyoma formation.

In premenopausal women, estrogen and progesterone hormone treatment probably has no inductive effect on leiomyoma formation. With few exceptions, oral contraceptive combination pills either lower or have no effect on this risk

Risk Factors


~During the reproductive years, the incidence of this tumor increases with age. After menopause, leiomyomas generally shrink in size and new tumor development is uncommon. Thus, it seems that most risk or protective factors depend on circumstances that chronically alter estrogen or progesterone levels or both.
~ Leiomyomas are common in African-American women compared with Caucasian, Asian, or Hispanic women.



Classification


Leiomyomas are classified based on their location and direction of growth















Symptoms
Most women with leiomyomas are asymptomatic. However, symptomatic patients typically complain of bleeding, pain, pressure sensation, or infertility. In general, the larger the leiomyoma, the greater the likelihood of symptoms.

Bleeding

This is the most common symptom and usually presents as menorrhagia*. The presence of the fibroids exert pressure on the venous system of the uterus, causing venous dilatation within the muscle and inner lining of the uterus, thus making it prone to heavier bleeding.

Pelvic Discomfort and Dysmenorrhea*

A sufficiently enlarged uterus can cause pressure sensation, urinary frequency, incontinence, and constipation. Rarely, leiomyomas extend laterally to compress the ureter (the structure that drains urine from each kidney and empties it into the bladder) and lead to obstruction and hydronephrosis *

Infertility and Pregnancy Wastage

Although the mechanisms are not clear, leiomyomas can be associated with infertility. It is estimated that 2-3% of infertility cases are due soley to leiomyomas. Their detrimental effects include occlusion of the openings that lead to each fallopian tube, and disruption of the normal uterine contractions that propel sperm or ova. Distortion of the uterine cavity may diminish implantation and sperm transport. Importantly, leiomyomas are associated with endometrial inflammation and vascular changes that may disrupt implantation.



On the next post....
So how are fibroids diagnosed, and what can be done about this common issue that many women face?

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Myometrium: middle layer of uterine wall consisting of smooth muscle cells and supporting stromal and vascular tissue
Menarche: the very first menstrual cycle that a human female experiences
Parity: The number of times a woman has given birth
Menorrhagia: abnormally heavy and prolonged menstrual period at regular intervals
Dysmenorrhea: severe uterine pain during menstruation
Hydronephrosis: distension and dilation of the kidney, usually due to obstruction of the outflow tract


Schorge JO, Schaffer JI, Halvorson LM, Hoffman BL, Bradshaw KD, Cunningham FG, "Chapter 9. Pelvic Mass" (Chapter). Schorge JO, Schaffer JI, Halvorson LM, Hoffman BL, Bradshaw KD, Cunningham FG: Williams Gynecology: http://www.accessmedicine.com/content.aspx?aID=3153525.