Most women with uterine fibroids don’t know they have them. At least half of all fibroids cause no symptoms at all and are only discovered during a routine exam or imaging for something else. When fibroids do cause problems, the signs tend to build gradually, making them easy to dismiss as “just a bad period” or general fatigue. Knowing what to look for can help you recognize when something has shifted from normal to worth investigating.
Heavy or Prolonged Periods
The most common and recognizable sign of fibroids is a change in your menstrual bleeding. A typical period lasts four to five days and involves about two to three tablespoons of blood loss total. With fibroids, periods often stretch beyond seven days, and the volume of blood lost can double or more.
Specific signs your bleeding may be fibroid-related:
- Soaking through a pad or tampon every hour for several hours in a row
- Needing to change your pad or tampon less than two hours after putting it in
- Doubling up on pads to keep up with the flow
- Waking up at night to change pads or tampons
- Passing blood clots the size of a quarter or larger
Not every fibroid causes heavy bleeding. The location matters. Fibroids that grow into the inner lining of the uterus (called submucosal fibroids) are the most likely to disrupt periods, while those growing on the outer surface may never affect your cycle at all.
Pelvic Pressure and Pain
Fibroids are physical growths, and as they get larger, they press on surrounding organs. This creates a constellation of symptoms that don’t always seem related to your reproductive system. Pelvic pressure or a sense of heaviness in the lower abdomen is common. Some women describe it as feeling like something is sitting on their bladder.
That bladder pressure is real. Fibroids can push against the bladder and cause frequent urination or difficulty fully emptying it. When they press against the rectum instead, constipation follows. Lower back pain and pain during sex are also typical, especially with larger fibroids or those positioned toward the back of the uterus. Some women notice their stomach area visibly growing, sometimes enough that others assume they’re pregnant.
In rare cases, a fibroid that hangs from a stalk (called a pedunculated fibroid) can twist on itself, cutting off its own blood supply. This causes sudden, severe abdominal pain that may come with nausea and vomiting. That scenario is a medical emergency.
Fatigue and Anemia You Can’t Explain
One of the less obvious signs of fibroids is persistent, unexplained fatigue. When your periods are consistently heavy, your body loses iron faster than it can replace it. Over time, this leads to iron-deficiency anemia, and you may not connect the dots because the bleeding has become your version of normal.
Anemia from fibroids can show up as exhaustion that sleep doesn’t fix, dizziness when standing, heart palpitations, and feeling short of breath during activities that didn’t used to wind you. In severe cases documented in medical literature, women with undiagnosed fibroids have presented with dangerously low blood counts requiring emergency treatment. If you’re tired all the time and your periods are heavy, those two facts are likely connected.
Who Is Most Likely to Develop Fibroids
Fibroids become more common with age through the reproductive years. Only about 5% of diagnoses occur in women under 30. The peak years are 40 to 49, which account for roughly half of all diagnosed cases. After menopause, fibroids typically shrink on their own as estrogen levels drop.
Race and ethnicity significantly affect risk. A 2024 study published in JAMA Network Open, which tracked fibroid diagnoses across a large integrated health system from 2009 to 2022, found that Black women were diagnosed at three times the rate of white women. South Asian women had 1.7 times the rate, East Asian women about 1.5 times, and Hispanic women about 1.4 times. South Asian women were also more likely to be diagnosed before age 35, a pattern not fully explained by the age makeup of the population studied. Family history plays a role too: having a mother or sister with fibroids increases your own risk.
How Fibroids Are Found
Many fibroids are discovered during a routine pelvic exam, when a doctor feels an irregularly shaped or enlarged uterus. But a physical exam alone can’t confirm the diagnosis. The standard next step is a transvaginal ultrasound, where a small probe is inserted to create images of the uterus. This is a quick, painless test that detects fibroids with roughly 89% sensitivity and over 99% specificity, meaning it catches most fibroids and very rarely mistakes something else for one.
If the ultrasound results are unclear, or if your doctor needs a more detailed map before treatment planning, an MRI provides sharper images and can distinguish between fibroids and other conditions. Sometimes a saline infusion sonogram is used, which fills the uterus with a small amount of fluid during ultrasound to better see fibroids that protrude into the uterine cavity.
Conditions That Mimic Fibroids
Several other conditions share symptoms with fibroids, which is why imaging matters. Adenomyosis is the closest mimic. Instead of a distinct growth, adenomyosis involves tissue from the uterine lining embedding itself into the muscular wall of the uterus. It causes heavy bleeding, painful periods, and an enlarged uterus, just like fibroids. The two conditions frequently coexist, and distinguishing between them usually requires MRI. Treatment options overlap but aren’t identical, so an accurate diagnosis changes the conversation about what to do next.
Endometrial polyps can also cause heavy or irregular bleeding. Ovarian cysts may produce pelvic pressure or pain. In rare cases, what appears to be a fibroid turns out to be a different type of growth entirely. This is another reason imaging is important rather than assuming based on symptoms alone.
What Symptoms Should Prompt Action
Because fibroids grow slowly and symptoms creep in over months or years, many women unconsciously adjust. They buy overnight pads for daytime use, cancel plans during their period, or chalk up their exhaustion to a busy life. If any of these situations sound familiar, it’s worth getting an ultrasound:
- Your periods have become noticeably heavier or longer than they used to be
- You feel constant pressure or fullness in your pelvis outside of your period
- You’re urinating more frequently without an obvious cause
- You’re fatigued in a way that rest doesn’t resolve
- Your abdomen has visibly grown without weight gain elsewhere
Sudden, severe pelvic or abdominal pain is a different category. While uncommon, fibroid torsion or degeneration (when a fibroid outgrows its blood supply and begins to die) can cause acute pain that requires emergency evaluation. If sharp pain comes on suddenly and is accompanied by nausea, vomiting, or fever, that needs same-day medical attention.