Key facts

  • Fibroids are one cause of heavy or abnormal uterine bleeding, and there are others as well1,5.
  • Heavy bleeding over time can lead to iron-deficiency anemia2,3,4,6.
  • Signs worth telling your doctor about: soaking through a pad or tampon every hour for several hours in a row, doubling up on protection, changing pads or tampons at night, periods longer than 7 days, and clots the size of a quarter or larger2.
  • Serious anemia can cause shortness of breath or chest pain3. If you are experiencing a medical emergency, call 911 or go to the nearest emergency room4.
  • Tests your doctor may use include a complete blood count, hemoglobin, iron, and ferritin. This page gives no cutoffs3.
  • Talk with your doctor before you decide. This information does not replace personal medical advice.

Fibroids and heavy bleeding

Uterine fibroids are one cause of abnormal or heavy uterine bleeding; there are other causes as well1,5. Heavy bleeding over time can lead to iron-deficiency anemia2,3,4,6, and tiredness from blood loss over time is a symptom of that anemia1. Your provider may prescribe iron supplements if you have anemia1.

Questions to ask

  • Do my fibroids look like the main driver of my bleeding, or could something else be contributing?
  • Would you want to check me for anemia based on what I'm describing?
  • What would change your sense of how heavy my bleeding really is?

Signs to flag for your doctor

Signs of heavy bleeding worth telling your doctor about include soaking through a pad or tampon every hour for several hours in a row, doubling up on protection, changing pads or tampons at night, periods longer than 7 days, and clots the size of a quarter or larger2. Separately, contact your provider if you soak through a pad or tampon every hour for 2 to 3 hours, or if bleeding increases or becomes severe enough to cause weakness or lightheadedness7.

Questions to ask

  • Which of these signs, if any, do you want me to track between now and my next visit?
  • Is there a point where you'd want to hear from me sooner than our next appointment?
  • How should I describe clot size or soaking frequency so it's useful to you?

When to get care right away

Serious anemia can cause shortness of breath or chest pain3. If you are experiencing a medical emergency, call 911 or go to the nearest emergency room4.

Tests your doctor may use

If anemia is a concern, tests your doctor may use include a complete blood count, hemoglobin, iron, and ferritin3. This page does not give specific cutoffs for any of these; ask your doctor what your own results show and what they mean for you.

Questions to ask

  • Which of these tests would you order for me, and why?
  • What do my results show, in plain terms?
  • Would you recheck any of these over time, and how often?

Treating anemia and heavy bleeding

Iron pills can take several months to restore iron levels. IV iron or a transfusion are used for more serious anemia3. Ask your doctor which approach, if any, fits your situation.

Before fibroid surgery, one hormone medicine (a GnRH agonist) is labeled for use together with iron therapy to improve blood counts in women with fibroid-related anemia when three months of hormone treatment is considered necessary, and its label suggests considering a one-month trial of iron alone first8. In a Cochrane review, this type of medicine before surgery probably raised blood counts, but it also came with a greater chance of side effects9.

Tranexamic acid decreases blood loss but does not stop menstrual bleeding10. Other options for fibroid-related heavy bleeding include a hormonal IUD, which can be used to control heavy bleeding, and procedures such as uterine fibroid embolization (UFE), myomectomy, and hysterectomy4. Each has different trade-offs, so ask which fit your goals. For more on medicine options, see medication for fibroids, and for a fuller comparison of every option, see non-surgical fibroid treatment and compare fibroid treatments. For background on fibroids themselves, see what are fibroids.

Questions to ask

  • Would it make sense to try iron alone before adding a hormone medicine?
  • Which medicine, if any, fits my situation, and for how long would I take it?
  • How would we know if a medicine is working for my bleeding or my blood counts?
  • Besides medicines, which procedures would you consider for my bleeding, and why?

Common questions

Can fibroids cause anemia?

Yes. Fibroids can cause heavy uterine bleeding, and heavy bleeding over time can lead to iron-deficiency anemia2,3,4,6.

How much bleeding is too much with fibroids?

Signs worth telling your doctor about include soaking through a pad or tampon every hour for several hours in a row, doubling up on protection, changing pads or tampons at night, periods longer than 7 days, and clots the size of a quarter or larger2. Separately, contact your provider if you soak through a pad or tampon every hour for 2 to 3 hours, or if bleeding increases or becomes severe enough to cause weakness or lightheadedness7.

When is fibroid bleeding an emergency?

Serious anemia can cause shortness of breath or chest pain3. If you are experiencing a medical emergency, call 911 or go to the nearest emergency room4.

What hemoglobin or ferritin levels should I ask about?

This page does not give specific cutoffs. Tests your doctor may use include a complete blood count, hemoglobin, iron, and ferritin3. Ask your doctor what your own results show and what they mean for you.

Are big clots normal with fibroids?

Clots the size of a quarter or larger are listed as a sign of heavy bleeding worth telling your doctor about, not something to assume is routine for you2. Ask your doctor whether what you're seeing fits that description.

Will fibroid treatment fix my anemia?

That depends on your treatment and your situation, so ask your doctor how your plan is expected to affect your blood counts, and over what timeframe.

Talk with your doctor before you decide. This information does not replace personal medical advice. Read the medical disclaimer.

Sources

  1. MedlinePlus, Abnormal uterine bleeding, reviewed 2024 ↩︎
  2. CDC, About Heavy Menstrual Bleeding, reviewed 2024 ↩︎
  3. NHLBI, Iron-Deficiency Anemia ↩︎
  4. Office on Women's Health, Uterine Fibroids, updated 2025 ↩︎
  5. ACR Appropriateness Criteria, management of uterine fibroids, 2023, PMID 38823944 ↩︎
  6. MedlinePlus, Uterine Fibroids, reviewed 2026 ↩︎
  7. MedlinePlus, Vaginal or Uterine Bleeding, reviewed 2024 ↩︎
  8. DailyMed, leuprolide acetate depot label, revised 2025 ↩︎
  9. Puscasiu et al., Cochrane review, preoperative medical therapy before surgery for fibroids, 2025, PMID 40183418 ↩︎
  10. MedlinePlus, Tranexamic Acid, revised 2017 ↩︎