The tricky thing about uterine fibroids is that most people who have them don’t know it. These noncancerous growths in or on the uterus affect nearly two-thirds of women by age 50, but only 20% to 50% ever develop noticeable symptoms. The rest are discovered by accident during a routine pelvic exam or imaging done for something else entirely. Still, when fibroids do cause symptoms, the signs tend to follow recognizable patterns.
Heavy or Prolonged Periods
The most common red flag is a change in your menstrual bleeding. Fibroids can make periods heavier, longer, or both. The CDC defines heavy menstrual bleeding as periods lasting more than seven days or flow heavy enough that you need to change a pad or tampon in less than two hours. Soaking through one or more pads every hour for several hours in a row, passing large clots, or having to get up at night to change protection all fall into this category.
Not every heavy period means fibroids, but if your flow has gradually worsened over months or years, fibroids are one of the most common explanations. The bleeding happens because fibroids distort the uterine lining, increasing its surface area and disrupting the normal process that stops menstrual flow. Over time, this blood loss can lead to iron-deficiency anemia, which brings its own symptoms: fatigue, dizziness, shortness of breath, and pale skin.
Pelvic Pressure and Pain
Fibroids range from the size of a seed to larger than a grapefruit. Small ones (under 5 cm) are roughly cherry-sized and often cause no physical sensation at all. Medium fibroids (5 to 10 cm) are closer to a plum or orange and may start pressing on surrounding structures. Large fibroids (over 10 cm) can grow to the size of a grapefruit or even a watermelon, and at that point, the pressure symptoms become hard to ignore.
What that pressure feels like depends on where the fibroid sits. Fibroids near the bladder create a frequent, urgent need to urinate even when your bladder isn’t full. Fibroids near the rectum can cause constipation, difficulty passing stool, or a persistent feeling of bloating and fullness in the lower abdomen even when you haven’t eaten much. Some women describe a general heaviness or aching in the pelvis that worsens during exercise or sex. Fibroids pressing on nerves in the lower back or legs can produce dull, aching pain or sharp, sudden pain in those areas.
A visibly bulging or swollen abdomen is another physical sign, particularly with large or multiple fibroids. Some women notice their pants fitting differently or are asked if they’re pregnant before they realize something else is going on.
Symptoms That Overlap With Other Conditions
Several fibroid symptoms, including heavy bleeding, pelvic pain, painful periods, fatigue, painful intercourse, and bladder or bowel problems, also show up in endometriosis. This overlap makes self-diagnosis unreliable. A few differences can help you and your doctor narrow things down. Endometriosis tends to appear in adolescence or early adulthood, while fibroids are more commonly diagnosed in women 40 and older. Bleeding between periods points more toward endometriosis than fibroids. A noticeably enlarged or bulging abdomen is more characteristic of fibroids.
Adenomyosis, ovarian cysts, and certain cancers can also mimic fibroid symptoms. The point isn’t to diagnose yourself from a list but to recognize which symptoms are worth investigating.
Who Gets Fibroids
Fibroids are extremely common across all demographics, but the risk isn’t evenly distributed. Black women are diagnosed roughly three times as often as white women, develop fibroids earlier, and tend to have larger, more numerous growths with more severe symptoms. National estimates suggest nearly a quarter of Black women between 18 and 30 already have fibroids, compared to about 6% of white women in the same age range. By 35, that figure rises to 60% for Black women.
Family history also matters. If your mother or sister had fibroids, your own risk is higher. Other factors linked to increased risk include starting your period at a young age, obesity, and a diet high in red meat. Having given birth appears to lower the risk.
How Fibroids Are Diagnosed
A doctor may suspect fibroids during a pelvic exam if the uterus feels enlarged or irregularly shaped, but imaging confirms the diagnosis. Ultrasound is the standard first step, and the type of ultrasound matters. Transvaginal ultrasound, where the probe is placed inside the vagina for a closer view, has an accuracy rate of about 96% and a sensitivity of 95% for classifying fibroids. The external (transabdominal) approach, where the probe moves across the abdomen, is significantly less precise, with roughly 71% accuracy and 80% sensitivity. In practice, doctors often use both together.
For more complex cases, particularly when surgery is being planned or when the ultrasound results are unclear, an MRI provides the most detailed picture of fibroid size, number, and exact location within the uterine wall. Blood tests don’t diagnose fibroids directly but can reveal anemia from chronic heavy bleeding, which supports the clinical picture.
What Fibroids Feel Like Day to Day
Many women describe the experience as a slow accumulation of “normal” that isn’t actually normal. You might spend years assuming everyone dreads their period or thinking it’s typical to get up twice a night to use the bathroom. The gradual progression makes it easy to adapt without realizing something has changed. A helpful exercise is to think back five years: are your periods heavier now? Do you urinate more often? Does your lower abdomen feel fuller or more uncomfortable than it used to?
Pain levels vary widely. Some women with large fibroids feel only mild pressure. Others with smaller fibroids in certain locations experience sharp, disruptive pain. The unpredictability is part of what makes fibroids frustrating. Symptoms can also shift with your menstrual cycle, flaring around your period and easing afterward, which sometimes leads women to dismiss them as “just bad cramps.”
Signs That Need Prompt Attention
Certain symptoms go beyond routine concern. Bleeding that soaks through protection every hour for several consecutive hours, pelvic pain that becomes unmanageable with over-the-counter options, significant abdominal swelling, or signs of anemia like extreme fatigue and lightheadedness all warrant a call to your provider sooner rather than later. Bleeding between periods is another symptom that should be evaluated, since it can point to fibroids, endometriosis, or other conditions that benefit from early diagnosis.