Uterine Fibroids and Infertilty (continuation)
Causes of Uterine Fibroids
Though a large percentage of women suffer from uterine fibroids, doctors are actually unsure of what causes them to occur. What they do know, however, is that estrogen and progesterone contribute to the growth of the fibroids.
Estrogen and progesterone are at their highest levels during a woman’s childbearing years; this is why uterine fibroids are thought to develop during this time. Normally, after a woman goes through menopause, her body produces lower levels of estrogen and progesterone causing the fibroids to begin to shrink and any associated symptoms, such as pain and pressure to subside.
Uterine fibroids are hormone dependent. They develop during the hormonally active years and decline in menopause.
Fibroid tissue has a higher amount of estrogen and progesterone receptors.
Fibroid tissue is hypersensitive to estrogen, but does not have the capacity to regulate the estrogen response; this is why they can grow to become quite large .
Other hormones play a role in the growth of uterine fibroids as well, including prolactin, parathyroid hormone, insulin growth factor, and pituitary growth hormone.
Fibroids are two to three times more likely to develop in African American women compared to any other ethnicity.
Factors that may increase fibroid development
• An increase in lifetime exposure to estrogen
There are many factors that increase a woman’s lifetime exposure to estrogen. More than at any other time in history, women are exposed to more estrogen. This increased exposure can contribute to a wide variety of reproductive health problems, including the development of uterine fibroids. The following factors increase a woman’s lifetime exposure to estrogen:
•Early menarche – the longer a woman has her menstrual cycle, the longer estrogen levels are elevated.
•Fewer pregnancies – many women today are restricting how many children they are having or are not having children at all, which increases their total exposure to estrogen.
•High body fat content – body fat produces and stores estrogen; the more body fat a woman has the more estrogen she has.
•Exposure to xenoestrogens – plastics, pesticides, herbicides, synthetic hormones in both meat and dairy products, and hormone replacement therapy (HRT) including oral contraceptives (birth control) containing synthetic estrogen.
•Poor estrogen metabolism – some women’s bodies have a harder time removing and metabolising excess estrogen.
In addition to exposure to estrogen, the following factors may also play a role in the development of uterine fibroids:
•Hypertension
•Infection complications from IUD use
•Perineal talc use
•Anovulatory cycles
•Endometrial hyperplasia (common in women with PCOS).