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Fibroids are non-cancerous little balls of muscle that start in the uterus's muscle wall and grow in response higher levels of estrogen. Most women after about age 30 are growing fibroids; however, most of us will never have any problems related to them. Very rarely fibroids can interfere with pregnancy, or grow so big that they cause urine or bowel blockage, bladder symptoms or pain. Fibroids shrink when women become menopausal.

Most women first learn that they have fibroids when they develop heavy flow (often in perimenopause). Because there is the wrong understanding that fibroids cause heavy flow, many family doctors will then order a uterine ultrasound. Very commonly this ultrasound shows fibroids. However that doesn't mean that the fibroids are causing the heavy flow. Higher estrogen levels cause both heavy flow and fibroid growth.

Fibroids tend to grow in three directions—within the muscle (the most common situation), pushing outside of the uterus (called subserosal or, if on a stalk, pedunculated) and into the endometrium (called submucosal). Submucosal fibroids are the only one of these three kinds of fibroids that could potentially cause abnormal vaginal bleeding—they make up less than 1 of every 10 fibroids. Instead, heavy bleeding is caused by the higher estrogen and lower progesterone levels of perimenopause and these hormonal changes make fibroids grow. Remember that fibroids are common and usually cause no problems.

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Enrolment complete: Perimenopausal Hot Flush Study

Enrolment is now complete. Thank you for your interest.
CeMCOR is now recruiting Canadian women for this CIHR-funded randomized controlled trial to test whether oral micronized progesterone is more effective than placebo as therapy for hot flushes and night sweats in perimenopausal women.



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