Seeing blood clots during your period can be alarming, especially if you’ve never noticed them before. Most of the time, small menstrual blood clots are a completely normal part of a heavier flow. However, in some cases, large or frequent blood clots may indicate an underlying condition that requires medical attention.
Below, we’ll explain what causes period blood clots, what’s considered normal, and when it’s time to speak with your OBGYN.
What Causes Blood Clots During Your Period?
Menstrual blood is more than just blood. It also contains uterine lining (endometrial tissue), mucus, and other fluids that your body sheds during menstruation.
As your uterus sheds its lining, your body releases natural anticoagulants that help keep menstrual blood flowing. If bleeding is especially heavy, your body may not produce enough anticoagulants to prevent clot formation. As a result, some blood clots before leaving the uterus.
Period blood clots may appear:
- Bright or dark red
- Jelly-like or thick in texture
- About the size of a dime or quarter
- Occasionally larger during heavier flow days
Passing an occasional blood clot, particularly during the first day or two of your period, is common for many women.
When Are Period Blood Clots Considered Normal?
Small blood clots are usually not a cause for concern if they occur during a heavier menstrual flow and aren’t accompanied by other symptoms.
In general, blood clots are more likely to be normal if they:
- Occur only during your menstrual period
- Are smaller than about the size of a quarter
- Appear on your heaviest flow days
- Occur only occasionally
Every person’s menstrual cycle is different, so what’s considered “normal” varies. The most important thing is noticing any significant changes in your usual menstrual pattern.
When Should You Be Concerned About Blood Clots?
Menstrual blood clots alone don’t necessarily indicate a medical problem, but they can sometimes be a sign of heavy menstrual bleeding or an underlying gynecologic condition.
You should schedule an appointment with your healthcare provider if you experience:
- Frequent blood clots larger than a quarter
- Bleeding that soaks through a pad or tampon every hour for two or more consecutive hours
- Periods lasting longer than seven days
- Severe pelvic pain or cramping
- Bleeding between periods
- Fatigue, dizziness, or symptoms of anemia
- A sudden change in your menstrual flow
These symptoms may warrant further evaluation to determine the underlying cause. Together, you and your OBGYN can identify what’s causing your symptoms and develop a treatment plan.
What Conditions Can Cause Large Blood Clots During Your Period?
Several medical conditions can contribute to heavier menstrual bleeding and larger blood clots, including:
Uterine Fibroids
Fibroids are noncancerous growths that develop within or on the uterus. Depending on their size and location, they can cause:
- Heavy menstrual bleeding
- Large blood clots
- Pelvic pressure
- Frequent urination
- Pain during menstruation
Adenomyosis
Adenomyosis occurs when tissue similar to the uterine lining grows into the muscular wall of the uterus. This condition commonly causes heavy, painful periods accompanied by clotting.
Hormonal Imbalances
Hormones regulate the buildup and shedding of the uterine lining. Conditions affecting hormone levels, such as polycystic ovary syndrome (PCOS), perimenopause, or thyroid disorders, may contribute to heavier periods.
Bleeding Disorders
Less commonly, inherited bleeding disorders or medications that affect blood clotting can contribute to unusually heavy menstrual bleeding.
Pregnancy-Related Causes
Heavy bleeding with clots during pregnancy or shortly after a positive pregnancy test should always be evaluated promptly, as it could indicate a miscarriage or another pregnancy-related complication.
How Are Heavy Periods and Blood Clots Evaluated?
If you’re experiencing unusually heavy bleeding, your healthcare provider will begin by reviewing your symptoms, menstrual history, and overall health.
Depending on your situation, your provider may recommend:
- A pelvic exam
- Blood tests to check for anemia or hormone imbalances
- A pelvic ultrasound
- Additional imaging or diagnostic procedures, if needed
These evaluations help identify the underlying cause of your symptoms and guide appropriate treatment recommendations.
What Treatments Are Available?
Treatment depends on the underlying cause of your heavy menstrual bleeding.
Options may include:
- Hormonal birth control
- Hormonal IUDs
- Non-hormonal medications to reduce menstrual bleeding
- Treatment for underlying hormone disorders
- Minimally invasive procedures for fibroids or other uterine conditions
- Surgery in select cases
Many women experience significant relief once the underlying cause has been identified and treated.
Don’t Ignore Changes in Your Menstrual Cycle
Occasional blood clots during your period are often completely normal, especially during heavier flow days. However, if you’re frequently passing large blood clots or experiencing unusually heavy bleeding, it’s important to discuss your symptoms with your healthcare provider.
Early evaluation can identify underlying conditions, provide effective treatment options, and help protect your long-term reproductive health.
Talking with a healthcare provider can help identify the cause of your symptoms and connect you with treatment options that improve comfort, confidence, and quality of life. Sometimes small changes make all the difference.