Fibroids: the common growths behind heavy periods
Last updated September 3, 2026.
Fibroids are non-cancerous muscle growths in or around the womb, and they are staggeringly common: most women will have them by age 50, and many never know. They are not cancer and do not turn into cancer. What they do is vary wildly: some sit silently for decades, others cause flooding periods, pelvic pressure, and fertility problems. Whether a fibroid needs treating depends on symptoms, size, position, and your plans, not on its mere existence.
What do they do?
The classic symptom is heavy periods: soaking through protection, clots, flooding accidents, periods lasting beyond a week, and the iron-deficiency anemia that follows (breathlessness, exhaustion, pale skin, hair shedding). Bulk symptoms come from size: pelvic pressure and a visible lower-belly swelling, needing to urinate often (fibroid pressing the bladder), constipation (pressing the bowel), and back or leg ache. Fibroids sitting in the womb cavity (submucosal) cause the worst bleeding and the most fertility trouble. During pregnancy most fibroids behave, but they raise the chance of pain episodes, breech position, and cesarean delivery.
How are they assessed?
A pelvic examination finds the enlarged, irregular womb; ultrasound confirms and maps them (size, number, position), sometimes with a saline-infusion scan or hysteroscopy for the cavity. Bloods check for the anemia the bleeding causes. An important rule: fibroids in a woman over 45 with new or changed bleeding still warrant the standard workup for that bleeding, because fibroids do not grant immunity from other causes. Rapidly growing masses after menopause, or any growth on hormone-blocking treatment, get investigated promptly rather than watched.
What actually helps?
- Watchful waiting when symptoms are mild: most fibroids need nothing but periodic review, and they shrink after menopause as hormone levels fall.
- Control the bleeding: the hormonal IUD (excellent for cavity-sparing fibroids), tranexamic acid during periods, NSAIDs, and iron tablets to repair the anemia.
- Shrink or starve them: GnRH medications (like relugolix-combination or leuprorelin) shrink fibroids and stop bleeding, used before surgery or as a bridge to menopause, with bone-protection add-back for longer courses.
- Remove or deprive them: myomectomy (surgical removal preserving the womb) when fertility matters; uterine artery embolization (blocking their blood supply) as a non-surgical option; hysterectomy as the definitive cure when family is complete and symptoms justify it.
- Match treatment to the actual problem: cavity fibroids causing fertility trouble are removed via hysteroscopy; bulk symptoms need bulk solutions. Position drives everything.
When is it an emergency?
Bleeding heavy enough to soak a pad or tampon every hour for several hours, or bleeding with dizziness, racing heart, breathlessness, or fainting, needs same-day assessment: that is significant blood loss. Sudden severe pelvic pain (a fibroid degenerating or a stalked one twisting) is same-day too, especially in pregnancy. Everything else is a planned-care conversation, and the pace of it is yours. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
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Common questions
Do fibroids turn into cancer?
No. Fibroids are benign muscle growths and do not become cancerous. The rare cancer that worries people, leiomyosarcoma, is thought to arise independently rather than from an existing fibroid, and it is very uncommon. The practical implication: a typical fibroid on ultrasound does not need removal to prevent cancer, and a slowly growing fibroid in a younger woman is expected behavior, not a red flag. Rapid growth after menopause is the scenario that gets investigated.
Will my fibroids go away after menopause?
They usually shrink, and symptoms usually stop, because fibroids are fed by estrogen and progesterone. Bleeding problems from fibroids typically resolve with menopause entirely. Two caveats: fibroids rarely disappear completely (they calcify and quiet down), and hormone replacement therapy can keep them ticking, which your prescriber factors in. New bleeding after menopause is never attributed to old fibroids; it always gets investigated on its own merits.
Can I get pregnant with fibroids?
Usually yes. Most women with fibroids conceive and deliver normally. The fibroids that matter for fertility are the ones distorting the womb cavity (submucosal, and some intramural), which can interfere with implantation and raise miscarriage risk; removing those hysteroscopically before IVF or when fertility is affected is standard. Fibroids elsewhere mostly need monitoring during pregnancy rather than treatment, though they raise the chance of pain episodes, breech position, and cesarean delivery.
What is the difference between a myomectomy and a hysterectomy?
Myomectomy removes the fibroids and keeps the womb: the choice when future pregnancy is the goal or when you want to keep your uterus for any reason. Its trade-off is that new fibroids can grow later. Hysterectomy removes the womb entirely: the only guaranteed permanent cure, ending both the fibroids and the periods, but ending fertility. Between them sit uterine artery embolization (cuts the fibroids' blood supply, no cutting) and focused ultrasound, which shrink rather than remove. The right choice is a genuine preference decision, not a hierarchy.
Why are my periods so heavy with fibroids?
Fibroids increase the womb's surface area, disrupt the normal clamping-down of blood vessels in the lining, and when sitting in the cavity, create raw surface that bleeds freely. The result is the soaking, clots, and flooding that define fibroid periods. The real danger is cumulative: months of heavy bleeding drain iron stores into anemia, which is where the exhaustion, breathlessness, and hair shedding come from. Checking and treating the iron is as important as treating the fibroid.
Are there medications that shrink fibroids?
Yes, two families. GnRH agonists and antagonists (leuprorelin injections, or the relugolix and elagolix combination tablets) switch off ovarian hormone production, shrinking fibroids by up to about half and stopping bleeding; they are used for a few months before surgery or as a bridge to menopause, with add-back hormones for longer courses to protect bones. When the medication stops, fibroids regrow, which is why they are a bridge or a test, not a stand-alone cure.