What Do Fibroid Blood Clots Look Like?

Blood clots passed during a period in someone with uterine fibroids tend to be dark red to deep maroon, often with a jelly-like or liver-like texture, and they can range from the size of a small coin to considerably larger. While anyone who menstruates can occasionally pass a small clot, what sets fibroid-related clots apart is their frequency, their size, and how often they coincide with flooding-level bleeding that soaks through protection. Understanding what these clots actually look like and when they cross the line from normal variation into something that needs medical attention is more nuanced than most health summaries suggest.

What Fibroid Clots Actually Look Like

Menstrual blood clots form when blood pools in the uterus or vagina long enough for the body’s natural clotting factors to kick in. In a typical period, clots are small, usually under a centimeter, and they pass without much notice. When fibroids are involved, the picture changes. The clots tend to be larger, sometimes the size of a golf ball or bigger, and they often have a dense, rubbery consistency. Their color ranges from bright red (when freshly formed) to very dark maroon or almost black (when blood has sat in the uterine cavity for a while before being expelled). Some people describe them as looking like raw liver or thick jam.

The texture can vary too. Some clots are smooth and gelatinous, essentially a mass of coagulated blood and fibrin. Others are more irregular with a slightly grainy surface, especially if they contain fragments of shed endometrial lining mixed in with the blood. Unlike a typical small clot that you might see once during a heavy day and then forget about, fibroid-associated clots can appear repeatedly throughout a period, sometimes with a gush of fluid that accompanies their passage. This flooding sensation is one of the hallmarks that distinguishes fibroid bleeding from an ordinary heavy period.

Why Fibroids Cause These Clots

Fibroids are benign muscular growths in the uterine wall, and their effect on bleeding depends heavily on where they sit. Submucosal fibroids, the type that bulges into the uterine cavity, are the biggest culprits for heavy bleeding and clot formation. They distort the lining of the uterus, increase the surface area that bleeds each cycle, and can interfere with the uterus’s ability to contract and squeeze blood vessels shut after shedding the endometrium. When the uterus cannot clamp down efficiently, blood pools, and pooled blood clots.

Interestingly, the relationship between fibroids and heavy bleeding is not as straightforward as it might seem. A study of over 900 women found that fibroids detected on ultrasound, taken as a group regardless of type, were not consistently associated with heavier menstrual blood loss or lower hemoglobin levels compared to women without fibroids on imaging. The critical distinction was the submucosal location. Women whose fibroids did not protrude into the uterine cavity often had bleeding patterns similar to women without fibroids at all.¹ So if you have been told you have fibroids but your periods are manageable, the location of those fibroids is likely the reason your experience differs from someone else’s.

How to Tell If Your Clots Are a Problem

Passing the occasional clot during a period is normal. Your body produces anticoagulants to keep menstrual blood flowing, but on the heaviest days, those anticoagulants can be overwhelmed, and small clots slip through. The general clinical threshold to watch for is clots larger than a quarter (roughly 2.5 centimeters across) or clots that appear frequently throughout multiple days of your period. If you are regularly passing clots of that size and soaking through a pad or tampon every hour or two, the bleeding has likely crossed into what clinicians consider heavy menstrual bleeding.

One practical tool that has been validated for distinguishing genuinely heavy bleeding from what just feels heavy is a pictorial blood-loss assessment chart. You record how soiled each pad or tampon is using a visual scale, and a score is tallied for each period. Research has shown that this type of visual self-assessment outperforms a person’s gut feeling about whether their periods are heavy and is even better than checking for anemia alone as a screening tool. One validated version found that using a specific score cutoff, the technique correctly identified heavy bleeding about 85 to 86 percent of the time.² This matters because many people with fibroids normalize years of heavy bleeding, assuming their experience is typical because they have never known anything else.

The Clot-to-Anemia Pipeline

The biggest downstream consequence of chronically passing large clots is iron-deficiency anemia, and it is strikingly common among people with symptomatic fibroids. A study of women with abnormal uterine bleeding found a high prevalence of both prolonged menstruation and passage of blood clots, and the most common structural finding on pelvic ultrasound was uterine fibroids. Women with fibroids in that group had lower average hemoglobin levels than those with normal imaging, and the link between pelvic abnormalities and the severity of anemia was statistically significant.³ The same study noted that women with fibroids and persistent heavy bleeding who also had the worst baseline anemia responded comparatively less well to oral iron supplementation, meaning the anemia can become difficult to correct without addressing the bleeding itself.

Symptoms of anemia build gradually and are easy to mistake for stress or poor sleep: fatigue, breathlessness on mild exertion, dizziness, pale skin or nails, and difficulty concentrating. If you have fibroids and recognize those symptoms alongside large or frequent clots, a simple blood count can tell you where you stand. Many people do not connect their exhaustion to their periods until a hemoglobin test makes the link obvious.

Symptoms Beyond the Clots

Heavy clotting during periods is usually the most visible fibroid symptom, but it rarely travels alone. A cross-sectional survey of nearly a thousand women with fibroids found that the most commonly reported symptoms were lower back pain (reported by about two-thirds), fatigue (also about two-thirds), bloating, and pelvic pain or cramping during menstruation. Heavy bleeding during periods was reported by just over half the group.⁴ Quality-of-life scores were consistently worse for women who experienced each symptom compared to women with fibroids who did not have that symptom, and the effect scaled with severity: women who rated their symptoms as severe scored dramatically lower across all quality-of-life measures.

This matters when you are evaluating your own situation. Clots might be the most alarming visual signal that something is off, but the broader symptom picture, including chronic fatigue that does not resolve with sleep, back pain that worsens around your period, and bloating that tracks with your cycle, all point to the same underlying problem. Treating the bleeding alone without addressing the fibroid may leave the other symptoms untouched.

When a “Clot” Is Not Actually a Clot

There is an unusual but important scenario worth knowing about: sometimes what passes vaginally and looks like a large blood clot is actually fibroid tissue. Submucosal fibroids can, on rare occasions, detach from the uterine wall and be expelled through the cervix. A case report described a premenopausal woman who passed a large structure that the medical team initially assumed was a blood clot. On closer examination and dissection, the mass turned out to be very hard, nothing like the soft, jelly-like consistency of a typical blood clot. It was a fibroid that had spontaneously expelled.⁵

Fibroid expulsion can also happen after certain treatments such as uterine artery embolization, where the blood supply to the fibroid is deliberately cut off, causing the growth to shrink and sometimes slough out. A retrospective analysis of women who underwent this procedure found that some experienced transvaginal passage of fibroid tissue during their recovery.⁶ If you pass something unusually firm, pale, or distinctly different in texture from a normal clot, particularly if it feels solid or rubbery rather than soft and gelatinous, save it (in a clean container) and bring it to your doctor. The distinction between a blood clot and fibroid tissue changes the clinical picture considerably.

Treatments That Reduce Clotting

Because the clots are a downstream effect of heavy uterine bleeding, treatment targets the bleeding itself. The approach depends on the fibroid’s size, number, location, and whether you want to preserve your fertility.

On the medication side, tranexamic acid is one of the more studied options specifically in the fibroid context. It works by stabilizing clots once they form, essentially helping the body’s own clotting system work more efficiently so less blood is lost. A systematic review concluded that tranexamic acid may reduce heavy menstrual bleeding in patients with fibroids, though it noted that the response likely varies with fibroid size and location.⁷ Hormonal options including progestin-releasing IUDs, combined oral contraceptives, and GnRH agonists can also thin the endometrial lining and reduce flow, though their effectiveness varies when fibroids are distorting the cavity.

For women who need a procedural intervention, uterine artery embolization (UAE) is a minimally invasive option that cuts off the fibroid’s blood supply. Clinical trials have reported symptom improvement rates of at least 85 percent in terms of menstrual loss after UAE.⁸ A retrospective study confirmed significant improvement in symptoms including heavy bleeding, painful periods, prolonged menstruation, and anemia after the procedure.⁶ Myomectomy, the surgical removal of fibroids while preserving the uterus, is another option, particularly for women planning future pregnancies. Tranexamic acid has also shown value during myomectomy surgery itself: a randomized controlled trial found that perioperative tranexamic acid infusion reduced average intraoperative blood loss by about 300 mL and total blood loss by over 500 mL compared to placebo, along with a meaningful improvement in post-surgery hemoglobin levels.⁹ Hysterectomy, removal of the uterus entirely, remains the only option that guarantees fibroids will not recur, but it is a permanent decision typically reserved for women who have completed childbearing and have not responded to other treatments.

What Can Influence How Heavy Your Bleeding Gets

Beyond the fibroids themselves, several other factors can affect how much you bleed each cycle and, by extension, how many and how large the clots you pass will be. A review of the determinants of menstrual blood flow identified modifiable factors including smoking, nutrition, exercise, stress, and weight fluctuation alongside non-modifiable ones like age, race, and genetics.¹⁰ This is worth keeping in mind because someone with a small, relatively quiet fibroid might find that their bleeding worsens during a period of high stress or significant weight change, not because the fibroid grew but because the hormonal and physiological environment shifted around it.

Adenomyosis, a condition where endometrial tissue grows into the muscular wall of the uterus, frequently coexists with fibroids and can amplify heavy bleeding and clotting independently. One study found that women with both fibroids and adenomyosis were more likely to have moderate-to-severe anemia.³ If treatment for fibroids alone does not bring your bleeding under control, adenomyosis is one of the conditions your doctor should be looking for as a contributing factor.

Clots During Perimenopause and the Approach to Menopause

Many people with fibroids hold on to the reassurance that fibroids will shrink after menopause, which is generally true since they depend on estrogen and progesterone to grow. But perimenopause, the years leading up to menopause, can be a wild card. Hormone levels fluctuate unpredictably during this time, and estrogen can actually surge before it eventually drops. For some women with fibroids, perimenopause brings the heaviest bleeding and worst clotting they have ever experienced, precisely when they expected things to be winding down.

This is also the stage of life when bleeding irregularities deserve extra attention. While fibroids themselves are benign, abnormal bleeding in the perimenopausal and postmenopausal years overlaps with presentations that need to be ruled out, including endometrial hyperplasia and, rarely, endometrial cancer. If your bleeding pattern changes significantly, especially if you start passing large clots after a period of relative calm, or if you experience any bleeding after your periods have stopped for twelve months, imaging and possibly an endometrial biopsy are warranted regardless of whether you have known fibroids.

Documenting What You See

One of the most practical things you can do if you are living with fibroid-related clots is to start documenting them. Clinicians have a limited window into your daily experience, and descriptions like “heavy” or “a lot of clots” mean different things to different people. A few specifics that are genuinely useful for your doctor:

Size comparison: Describe clots relative to familiar objects. A dime, a quarter, a golf ball. If you are comfortable, photograph them next to a coin for scale.
Frequency per day: Note whether you are passing one large clot on day two of your period or multiple clots every few hours for several days.
Pad or tampon count: Track how many you go through and how saturated each one is. Soaking through a regular pad in under an hour is a red flag worth reporting.
Color and texture: Dark and jelly-like versus bright red and loose versus unusually firm. These distinctions can help your doctor differentiate between a blood clot and something else, like expelled tissue.
Associated symptoms: Record fatigue levels, dizziness, cramping intensity, and whether the clots are accompanied by a gush of blood.

This kind of record turns a vague complaint into actionable clinical data. It also provides a baseline so that if your doctor recommends a treatment, you both have a way to measure whether it is working. The validated pictorial charts mentioned earlier are one structured way to do this, but even informal notes kept on your phone over two or three cycles can make a real difference in the quality of your medical conversations.