Uterine fibroids are one of the most common reasons women see a clinician about heavy periods or pelvic pressure — yet many people who have them never know. They are usually harmless, often need no treatment, and tend to settle after menopause. Here is what they are, why they cause the symptoms they do, and the options worth understanding.
What are uterine fibroids?
Fibroids are common, usually non-cancerous growths made of muscle and fibrous tissue that develop in or on the wall of the uterus. They are sometimes called myomas or leiomyomas. They are very common in the reproductive years — especially in the 30s to 50s — and their growth is influenced by estrogen and progesterone, the hormones that rise and fall across the menstrual cycle.
Fibroids range from too small to see to the size of a melon, and you can have one or many. The exact cause isn't fully understood, but family history and hormone exposure both play a role. Importantly, fibroids themselves are not precancerous, and the vast majority are benign.
Types of fibroids by location
Where a fibroid sits matters far more than its size when it comes to symptoms. Fibroids are grouped by their position in the uterus.
| Type | Where it grows | Typical effect on symptoms |
|---|---|---|
| Submucosal | Bulging into the uterine cavity, under the lining | Most likely to cause heavy bleeding and fertility problems, even when small |
| Intramural | Within the muscular wall of the uterus | Can cause heavy periods, cramping and a feeling of fullness as they grow |
| Subserosal | On the outer surface of the uterus | More likely to press on nearby organs — bladder or bowel — than to cause heavy bleeding |
| Pedunculated | On a stalk, inside or outside the uterus | Can occasionally twist, causing sudden pain; otherwise depends on direction of growth |
Common fibroid symptoms
Many fibroids cause no symptoms at all and are found by chance during a scan or pelvic exam. When symptoms do occur, they often reflect a fibroid's size and location. Common ones include:
- Heavy or prolonged periods. This is the classic sign, especially with submucosal fibroids. Persistent heavy bleeding is worth understanding in its own right — see our guide to heavy periods — because regular blood loss can lead to iron-deficiency anemia.
- Pelvic pressure or pain. Larger fibroids can create a dragging, full or heavy sensation low in the abdomen. If you have ongoing discomfort, our overview of pelvic pain may help you make sense of it.
- Frequent urination or difficulty fully emptying the bladder, when a fibroid presses forward onto it.
- Bloating or a visibly fuller lower abdomen.
- Pain during sex, particularly with certain positions.
- Constipation or pressure on the bowel.
- Sometimes fertility difficulties, mainly when fibroids distort the uterine cavity.
Fibroid symptoms overlap with other conditions such as adenomyosis, endometriosis and ovarian cysts, which is part of why getting a proper assessment matters. Fibroids are also sometimes confused with PCOS, but the two are different: PCOS is a hormonal condition linked to irregular ovulation, whereas fibroids are physical growths in the uterus — see our guide to PCOS symptoms for the distinction.
What causes fibroids?
No single cause explains fibroids, but several factors are linked to them:
- Hormones. Estrogen and progesterone encourage fibroid growth, which is why fibroids rarely appear before puberty and often shrink after menopause.
- Family history. Having a mother or sister with fibroids raises your likelihood.
- Age and reproductive years. They become more common with age until menopause.
- Other factors studied include earlier first periods and ethnicity, with fibroids being especially common in Black women, who may also develop them younger and have larger or more numerous fibroids.
How are fibroids diagnosed?
Diagnosis is usually straightforward. A clinician will ask about your periods and symptoms and may carry out a pelvic exam, during which a larger fibroid can sometimes be felt as an irregularity in the uterus.
The main test is an ultrasound — either over the abdomen or internally (transvaginal) — which shows the number, size and location of fibroids. In some cases other imaging, such as an MRI, or a look inside the uterine cavity (hysteroscopy) is used to plan treatment. If bleeding has been heavy, a blood test may check for anemia.
Fibroids treatment options
Treatment depends on your symptoms, the size and position of the fibroids, your age, and whether you hope to become pregnant. The options below are described in general terms, not prescribed — what's right for you is a decision to make with a clinician.
Watchful waiting
If fibroids are small and not bothering you, no treatment may be needed. Many can simply be monitored, especially as menopause approaches and they're likely to shrink.
Medications
Medication doesn't remove fibroids but can ease symptoms — particularly bleeding:
- Tranexamic acid, a non-hormonal medicine taken during periods to reduce heavy bleeding.
- Hormonal options such as a hormonal IUD, the combined pill or other hormonal treatments, which can lighten periods. (If you're weighing non-hormonal routes generally, see non-hormonal birth control.)
- GnRH analogues. GnRH agonists temporarily shrink fibroids and stop periods, often used for a limited time before surgery. Newer GnRH antagonist combination tablets (with low-dose hormonal "add-back") can also reduce heavy bleeding over a longer period without the same menopausal side effects.
- Iron supplements if blood loss has caused anemia.
Procedures
When symptoms are significant, several procedures may be considered:
- Uterine artery embolization — blocking the fibroid's blood supply so it shrinks, done by an interventional radiologist.
- Myomectomy — surgical removal of fibroids while keeping the uterus, an option for those wishing to preserve fertility.
- Endometrial ablation or other minimally invasive techniques to reduce bleeding.
- Hysterectomy — removal of the uterus, the only definitive cure, considered when other options aren't suitable and childbearing is complete.
Fibroids and menopause
Because fibroids feed on estrogen, they commonly shrink and cause fewer symptoms after menopause, when hormone levels fall. For many women, that means a problem that loomed large in their 40s quietly settles — see how this timing works in our guide to menopause age. A few caveats are worth knowing: fibroids are less likely to regress in Black women, and menopausal hormone therapy (HRT) containing estrogen can sometimes maintain or stimulate fibroids, so it's worth mentioning a history of fibroids when discussing HRT. Most importantly, any vaginal bleeding that happens 12 or more months after your last period (postmenopausal bleeding) is not normal and should always be checked promptly.
When to see a clinician
Fibroids are very common and most are harmless, but some symptoms deserve attention. Make an appointment if you have:
- Heavy or prolonged periods, or bleeding between periods.
- Pelvic pressure, pain, bloating, or frequent urination that disrupts daily life.
- Signs of anemia — extreme tiredness, breathlessness or unusual pallor.
- Difficulty becoming pregnant.
- A fibroid that seems to be growing quickly, or a new lump or mass in your lower abdomen — particularly after menopause. This is very rarely a cancer (a uterine sarcoma can occasionally look like a fibroid), but it is worth checking promptly for peace of mind.
Period pain or pelvic pain that interferes with your life is not something simply to endure — it can signal fibroids, endometriosis or adenomyosis, and delays in diagnosis are common, so it's worth advocating for proper assessment.
Seek urgent or emergency care for very heavy bleeding (soaking through protection every hour, large clots, or flooding), or for sudden, severe pelvic or abdominal pain, especially with nausea, vomiting, fever, dizziness or fainting — which can occasionally signal a twisted (pedunculated) fibroid or another emergency. Any bleeding 12 or more months after your last period must be checked promptly. This guide is educational and is not a diagnosis or a substitute for personal medical advice.
