Uterine fibroids are detected through a combination of symptom recognition, a physical exam, and imaging. Most fibroids are found during a routine pelvic exam when a doctor notices the uterus feels enlarged or irregular, but an ultrasound is the standard tool for confirming them. Many women with fibroids have no symptoms at all, so understanding what to look for and what tests to expect can help you get answers faster.
Symptoms That Signal Fibroids
Fibroids don’t always announce themselves. Many women discover them incidentally during a routine exam or an unrelated scan. But when fibroids do cause symptoms, they tend to follow a recognizable pattern:
- Heavy or prolonged periods that soak through pads or tampons quickly, or last longer than seven days
- Bleeding between periods
- Pelvic pressure or fullness, often described as a heaviness or bloating in the lower belly
- Frequent urination, caused by a fibroid pressing against the bladder
- Pain during sex
- Lower back pain that doesn’t have an obvious musculoskeletal cause
- Anemia, which shows up as fatigue, dizziness, or shortness of breath from chronic blood loss
Reproductive issues can also point to fibroids. Recurrent miscarriages, difficulty conceiving, and preterm labor are all associated with them. If you’re experiencing a combination of these symptoms, especially heavy bleeding alongside pelvic pressure, fibroids are high on the list of likely causes.
What You Can Check at Home
You can’t diagnose fibroids on your own, but you can notice certain signs. Large fibroids sometimes cause visible swelling in the lower abdomen. If you lie flat on your back with relaxed abdominal muscles and feel a firm, rounded mass above your pubic bone, that’s worth bringing up with your doctor. Very large fibroids can make the belly look noticeably distended, similar to early pregnancy.
Smaller fibroids, which are far more common, aren’t detectable by touch. The more useful self-check is tracking your symptoms. Keep a simple log of your period length, how many pads or tampons you use per day, any pain or pressure you feel, and how often you’re getting up at night to urinate. This kind of record gives your doctor a clear starting point and can speed up diagnosis.
The Pelvic Exam
A pelvic exam is usually the first clinical step. During this exam, your doctor places one or two gloved fingers inside the vagina while pressing on your lower abdomen with the other hand. This allows them to feel the size, shape, and texture of the uterus. A uterus with fibroids often feels enlarged, lumpy, or asymmetrical rather than smooth and pear-shaped.
A pelvic exam can detect fibroids that are large enough to change the contour of the uterus, but it can’t identify smaller growths or tell fibroids apart from other conditions. That’s why imaging almost always follows.
Ultrasound: The First-Line Imaging Test
Pelvic ultrasound is the standard first imaging test for fibroids, recommended by the American College of Radiology. There are two types, and their accuracy is significantly different.
A transabdominal ultrasound uses a wand moved across the outside of your belly. It gives a broad view of the uterus and surrounding organs. Its accuracy for classifying fibroids is about 71%, with a sensitivity of around 80%. It’s useful for getting an overall picture, especially when the uterus is very large.
A transvaginal ultrasound uses a slim probe inserted into the vagina, placing the sensor much closer to the uterus. This version is significantly more precise, with an accuracy of about 96% and a sensitivity of 95%. It can detect smaller fibroids and show their exact location within the uterine wall. In a 2024 study comparing both methods against surgical findings, the transvaginal approach was far superior for correct classification.
Many clinics use both approaches in the same appointment. The transabdominal scan maps the overall anatomy, while the transvaginal scan zeros in on detail. Neither one is painful, though the transvaginal probe can feel mildly uncomfortable. The whole process typically takes 15 to 30 minutes.
Sonohysterogram for a Closer Look Inside
If your doctor suspects a fibroid is growing into the uterine cavity (called a submucosal fibroid), a standard ultrasound may not give enough detail. A sonohysterogram adds one extra step: sterile saline is gently infused through a thin catheter into the uterus before the transvaginal ultrasound is performed. The fluid expands the uterine cavity like a balloon, making the inner walls and any growths protruding into that space much easier to see.
This test is particularly important if you’re dealing with heavy bleeding or fertility concerns, since submucosal fibroids are the type most likely to affect both. The saline infusion can cause brief cramping similar to a period cramp, but it passes quickly. The entire procedure takes about 15 minutes.
MRI for Complex or Surgical Cases
MRI provides the most detailed map of fibroids. It shows the exact number, size, and precise location of every fibroid, and it helps distinguish fibroids from other conditions that can mimic them on ultrasound. Your doctor is most likely to order an MRI if you have a large or complicated fibroid, if surgery or a specialized procedure is being considered, or if ultrasound results are unclear.
One of the key situations where MRI adds value is telling fibroids apart from adenomyosis. Both conditions can enlarge the uterus and cause heavy bleeding, and they sometimes coexist. On ultrasound, fibroids appear as distinct, rounded masses with blood vessels concentrated around their edges. Adenomyosis looks different: the uterine muscle appears generally thickened with a blurred inner boundary and may contain tiny cysts. MRI makes this distinction more reliably than ultrasound alone, which matters because the two conditions are treated differently.
Hysteroscopy: Direct Visualization
A hysteroscopy lets your doctor look directly inside the uterus using a thin, lighted telescope inserted through the cervix. Saline is used to gently expand the uterine cavity so the walls and any growths are clearly visible. This is the most definitive way to identify submucosal fibroids and can sometimes be combined with treatment in the same session, removing a small fibroid on the spot.
Hysteroscopy is typically performed in an office or outpatient setting. It can be done with local anesthesia or light sedation. You may feel cramping during the procedure, and mild spotting afterward is normal. It’s not a routine screening tool. It’s used when imaging has already raised a specific question about the inner lining of the uterus.
Blood Tests That Support the Diagnosis
Blood tests don’t detect fibroids directly, but they reveal the toll fibroids may be taking on your body. A complete blood count checks your hemoglobin and red blood cell levels. Chronic heavy bleeding from fibroids frequently causes iron-deficiency anemia, which explains the fatigue, weakness, and lightheadedness many women experience. If your hemoglobin is low and you’ve been having heavy periods, that combination strongly suggests fibroids as the underlying cause.
Your doctor may also check thyroid function and other hormone levels to rule out alternative explanations for abnormal bleeding before attributing everything to fibroids.
What the Diagnostic Process Looks Like in Practice
Most women follow a predictable path. You notice symptoms or your doctor feels something during a routine exam. The next step is a transvaginal ultrasound, which confirms whether fibroids are present and shows where they are. If the ultrasound is sufficient, no further imaging is needed, and your doctor can discuss monitoring or treatment options based on the size, number, and location of the fibroids and how much they’re affecting your life.
If the picture is more complicated, a sonohysterogram, MRI, or hysteroscopy fills in the gaps. The specific test depends on what question needs answering: is the fibroid inside the cavity, is it really a fibroid and not adenomyosis, or how many are there before planning a procedure? Not everyone needs every test. Most women get their answer from the ultrasound alone.