Can Fibroids Be Dangerous? What to Know

Uterine fibroids (also called leiomyomas) are noncancerous growths of the uterus that are extremely common during the reproductive years. Most fibroids never cause harm. Still, some can lead to significant symptoms or complications that deserve timely medical attention. This guide explains when fibroids can be dangerous, how they are diagnosed, and the most up-to-date, evidence-based treatments.

What Are Fibroids, and How Common Are They?

Fibroids grow from the muscle tissue of the uterus. They can be single or multiple and vary in size from a pea to larger than a grapefruit. Many people have no symptoms, while others experience heavy periods, pelvic pressure, or fertility challenges. By age 50, fibroids affect the majority of women; estimates from the National Institutes of Health suggest up to about 70% of White women and more than 80% of Black women will develop them by that age (NIH/NICHD).

Are Fibroids Dangerous?

In most cases, fibroids are not dangerous and do not turn into cancer. The main concern is how they affect quality of life and health through bleeding, pain, or pressure symptoms. A very rare cancer called uterine sarcoma can appear similar to fibroids before surgery, but the risk of an unsuspected sarcoma at the time of surgery for presumed fibroids is low. The American College of Obstetricians and Gynecologists (ACOG) cites estimates ranging from about 1 in 770 to less than 1 in 10,000 cases, reflecting different study methods (ACOG). The U.S. Food and Drug Administration (FDA) has also issued safety communications around surgical techniques because of this rare risk (FDA).

When Can Fibroids Become a Serious Health Issue?

• Heavy menstrual bleeding and anemia: Fibroids can cause heavy or prolonged periods that lead to iron-deficiency anemia, with symptoms such as fatigue, shortness of breath, or dizziness (Office on Women’s Health, HHS). Severe anemia can be dangerous if untreated.
• Severe pelvic pain or acute events: A pedunculated fibroid (on a stalk) can twist (torsion), causing sudden, intense pain. Degeneration (when a fibroid outgrows its blood supply) can also cause acute pain and fever.
• Pressure on nearby organs: Large fibroids may press on the bladder, causing frequent urination or urinary retention, or on the bowel, leading to constipation. Rarely, obstruction of urinary flow may affect kidney function if not addressed.
• Pregnancy-related complications: While many people with fibroids have healthy pregnancies, fibroids can increase the risk of certain complications, including cesarean delivery, fetal malposition, preterm birth, placental problems, and postpartum hemorrhage. The risks depend on the size, number, and location of fibroids (NIH/NICHD).

Who Is at Higher Risk of Problematic Fibroids?

Risk factors for developing fibroids or having more severe disease include Black race, family history, earlier onset of menstruation, and higher body weight. Fibroids typically grow during the reproductive years and often shrink after menopause as estrogen levels fall (MedlinePlus/NIH; OWH).

Common Symptoms to Watch For

• Heavy menstrual bleeding (soaking through pads or tampons every hour for several hours, passing large clots)
• Periods lasting more than 7 days
• Pelvic pressure or fullness, bloating
• Frequent urination or difficulty emptying the bladder
• Constipation
• Pelvic pain or pain during sex
• Back or leg pain (from pressure on nerves)

Seek urgent care for severe pain, fainting, paleness with shortness of breath, or if you soak through one or more pads/tampons per hour for more than two consecutive hours.

How Fibroids Are Diagnosed

Diagnosis usually starts with a pelvic exam and ultrasound. Transvaginal ultrasound is common, while saline infusion sonohysterography or hysteroscopy can better evaluate fibroids that protrude into the uterine cavity. MRI is sometimes used for surgical planning or when the diagnosis is uncertain. In those with abnormal uterine bleeding—especially age 45 and older or with risk factors—endometrial sampling may be recommended to rule out other causes (ACOG patient guidance).

Evidence-Based Treatment Options

The “right” treatment depends on your symptoms, fibroid size and location, age, and whether you want future fertility. Options include:

Watchful waiting

If fibroids are small and not bothersome, monitoring with periodic exams and imaging may be enough. Many shrink after menopause.

Medications

• Nonhormonal: NSAIDs can relieve cramps; tranexamic acid reduces heavy bleeding during periods (taken only on bleeding days).
• Hormonal methods: Combined pills, progestin-only methods, and the levonorgestrel intrauterine device (IUD) can lessen bleeding and cramps.
• GnRH-based therapies: Short-term use of gonadotropin-releasing hormone (GnRH) agonists can shrink fibroids and correct anemia before surgery. Newer oral GnRH antagonists with add-back therapy are FDA-approved for heavy menstrual bleeding associated with fibroids, including elagolix combination therapy (Oriahnn) and relugolix combination therapy (Myfembree) (FDA on Oriahnn; FDA on Myfembree).
• Iron supplementation: If anemia is present, iron therapy and dietary iron may be recommended under clinician guidance.

Minimally invasive procedures

• Hysteroscopic myomectomy: Removes fibroids located inside the uterine cavity; often an outpatient procedure and preserves the uterus.
• Uterine artery embolization (UAE): An interventional radiology procedure that shrinks fibroids by blocking their blood supply; typically short recovery. Not ideal for everyone seeking future fertility (MedlinePlus/NIH).
• MRI-guided focused ultrasound (MRgFUS): Noninvasive ultrasound energy targets fibroids under MRI guidance; appropriate for select patients.
• Radiofrequency ablation: Heat energy is used laparoscopically or transcervically to shrink fibroids; may be suitable for certain sizes and locations.

Surgery

• Myomectomy: Surgical removal of fibroids with preservation of the uterus. Can be hysteroscopic, laparoscopic/robotic, or open (abdominal), depending on fibroid size, number, and location.
• Hysterectomy: Complete removal of the uterus; definitively treats fibroids and bleeding but ends fertility.

Ask your surgeon about the approach and safety measures. Because of the rare risk of an unsuspected sarcoma, the FDA advises that power morcellation be restricted to carefully selected patients and, when used, performed only with FDA-cleared containment systems in appropriate candidates (FDA).

Fibroids, Fertility, and Pregnancy

Not all fibroids affect fertility. Those that distort the uterine cavity (submucosal) are more likely to reduce natural conception and may increase miscarriage risk. Hysteroscopic removal can improve outcomes in selected cases. During pregnancy, many people with fibroids do well, but careful monitoring is advised because of increased risks of malpresentation, preterm birth, cesarean delivery, and postpartum hemorrhage, depending on fibroid characteristics (NIH/NICHD). If you are pregnant or planning pregnancy and have fibroids, consult an obstetric provider early.

Myths and Facts

• Do fibroids turn into cancer? No. Fibroids are benign and do not transform into cancer. The concern is the rare presence of a different, preexisting cancer (uterine sarcoma) that can resemble fibroids before surgery. Uterine size or rapid growth alone is a poor predictor of sarcoma (ACOG).
• Will fibroids go away after menopause? Many shrink after menopause as hormone levels fall, but symptoms and growth patterns vary.

When to Seek Care

• Heavy bleeding that soaks through pads/tampons hourly for more than two hours
• Symptoms of anemia (fatigue, dizziness, shortness of breath, chest pain)
• Severe or sudden pelvic pain
• Urinary retention or inability to pass urine
• Concerns about fertility or pregnancy with known fibroids

Your clinician can help differentiate fibroids from other causes of abnormal bleeding or pelvic pain and tailor a plan that matches your goals.

Trusted Sources and Further Reading

• NIH/NICHD: Uterine Fibroids
• U.S. Office on Women’s Health (HHS): Uterine Fibroids
• MedlinePlus/NIH: Uterine Fibroids
• ACOG: Uterine Morcellation for Presumed Leiomyomas
• FDA Safety Communication: Laparoscopic Power Morcellators
• FDA Drug Approvals: Oriahnn (elagolix combination); Myfembree (relugolix combination)

This article is for general education and does not replace personalized medical advice. If you suspect you have fibroids or are experiencing concerning symptoms, consult a qualified healthcare professional.