Basic Information about Fibroids and Female Anatomy

Female Pelvic Anatomy.

The female reproductive system consists of the vagina, cervix, uterus, fallopian tubes and the ovaries. These organs are all contained within the female pelvis.

The uterus (womb) is a pear shaped organ located between the bladder and the rectum. The uterus is made up fibro muscular, smooth muscle walls and a glandular lining. The fertilized egg implants into this lining when pregnancy occurs. This lining also sheds off during the menstrual period if pregnancy does not occur. The muscular walls are able to expand enormously during pregnancy to accommodate the growing fetus.

The cervix, often described separately, is actually part of the uterus. It is the lowermost part of the uterus and has a narrow passage through which menstrual blood passes during a woman’s period. The cervix protrudes into the upper vagina and serves as an entryway into the uterus and also serves to hold the uterus closed during pregnancy.

The fallopian tubes are small muscular tubes, which are located on either side of the upper uterus. It is through these tubes that the egg will pass following ovulation into the uterus. Fertilization usually occurs in the fallopian tube.

The ovaries are tethered to the upper aspect of the uterus, in close proximity to the ends of the fallopian tubes. The ovaries release one egg during every cycle. They also make the two main female hormones, estrogen and progesterone.

What are fibroids?

Fibroids, also known as myomas, fibromyomas or leiomyofibromas are the most common pelvic tumor in women. They are generally round firm growths that develop within the uterus. They are almost always benign (non cancerous) and can range in size from microscopic to as large as a melon.

What causes fibroids?

Scientists are not sure what cause fibroids to grow. It is thought that they develop from a normal myometrial (uterine muscle) cell, which mutates due to the influence of estrogen and progesterone and other local growth factors. Fibroids may grow during pregnancy due to the high levels of hormones. Conversely, after menopause, fibroids often shrink due to decreased hormone levels.

Who is affected by fibroids?

Fibroids are very common. It is estimated that anywhere from 20-50% of all women have these benign growths. They are also more likely to effect women in their 30s and 40s. Some ethnic variability exists as well, with as many as 50% of African American women having fibroids in their reproductive years versus 25% in Caucasian women. It is not known why fibroids develop in some women and not in others. Fibroids are the most common indication for hysterectomy in the United States.

What happens to fibroids over time?

Some fibroids continue to grow steadily over the reproductive years while others may stay the same size. Fibroids generally stop growing after menopause when hormone levels diminish. Fibroids that continue to grow after menopause should be evaluated.

When should I consider treatment?

Most fibroids, even large ones, do not produce significant symptoms. If a woman is not bothered by her fibroids, she probably does not need to have treatment. If however, symptoms develop, she should be evaluated by her gynecologist.