Detailed definition
Uterine fibroids (leiomyomas, myomas) are benign monoclonal tumors arising from myometrial smooth muscle. They are extremely common — by age 50, approximately 50–80% of women have at least one fibroid. They range from a few millimeters to large pelvic masses. Symptomatic fibroids cause heavy menstrual bleeding (menorrhagia), pelvic pressure or pain, urinary frequency, dyspareunia, and reproductive complications. Fibroids are estrogen-responsive — they typically grow in the reproductive years and shrink in postmenopause. Treatment options for symptomatic fibroids include the LNG-IUD (for bleeding), GnRH agonists or antagonists (for short-term shrinkage), uterine artery embolization, focused ultrasound, myomectomy, and hysterectomy. Postmenopausal women with prior fibroids generally see them remain stable or shrink; HRT at standard menopause doses rarely causes meaningful regrowth.
Why it matters in menopause
For perimenopausal women with heavy bleeding from fibroids, the LNG-IUD is often a particularly useful option — addressing bleeding and providing endometrial protection if HRT is added later. Fibroids alone are not a contraindication to HRT.