Here's When to See a Doctor About Menstrual Blood Clots


Among the women’s health topics that don’t get enough attention, menstrual blood clots are an important one. Many women experience menstrual blood clots at some point or another. But knowing which blood clots are a normal part of menstruation and which might warrant a trip to the doctor tends to be a bit of a mystery to many.

And well, we’re not really okay with that. Because while some menstrual blood clots aren’t a problem, these clots could be associated with a medical condition other times, and you might require some healthcare.

We want to make sure you know and understand the important details on menstrual blood clots, including their causes, associated conditions, and some signs that let you know it’s time to see a doctor. Keep reading to find out everything you need to know.

Meet the Expert

  • Nicole Williams is a  board-certified OBGYN and founder of The Gynecology Institute of Chicago. 
  • Natalie Crawford is a board-certified OBGYN.
  • Betsy Greenleaf is a board-certified OBGYN and female urogynecologist.

What Are Menstrual Blood Clots?

First things first: menstrual blood clots are not the same type of blood clot, also known as deep vein thrombosis (DVT), which travels in the bloodstream and blocks blood flow. Instead, “menstrual clots leave the body and indicate that blood is acting as we expect,” says Nicole Williams, who is a  board-certified ObGyn and founder of The Gynecology Institute of Chicago. 

Blood clotting is a normal body function that helps us stop bleeding, and menstrual blood clots can be a completely normal part of menstruation. Usually, menstrual blood clots are a response to heavy bleeding or blood that accumulates more quickly than it can be broken down, explains Natalie Crawford, a board-certified ObGyn.

“When blood is sitting stagnant for more than a few seconds, the platelets in the blood cause it to stick together,” Williams says. “This is a clot. These types of clots help to close the tiny blood vessels which are left when tissue falls off in menstruation.”

Those of you who use a menstrual cup may notice blood clots when emptying your cup. Because the blood often sits in your menstrual cup for a few hours, it might naturally separate into liquid and clotted portions.

What Are Some Common Causes of Menstrual Blood Clots?

Experiencing menstrual blood clots doesn’t always mean you have a serious medical condition going on. Sometimes, a small amount of clotting is normal and natural, especially during the early days of your period.

“When you have a period, your progesterone drops, and this signals that it is time for your uterus to shed the endometrium,” Crawford says. “Under the endometrium are many small blood vessels which result in bleeding.”

She explains that typically, this blood is broken down by anticoagulants in the blood, but sometimes blood clotting can occur, especially when bleeding occurs more quickly.

Generally, menstrual blood clots are more common on the heavier days of your flow. On these heavier flow days, you might have more blood sitting in your vagina or the lower part of the uterus before it leaves the body. Williams explains that this blood will naturally clot itself.

Sometimes, what we interpret as a menstrual blood clot isn’t what it seems. In some cases, people see clumps of endometrium tissue in their menstrual flow—which is normal—and mistakenly believe this is a blood clot, Crawford tells us.

What Underlying Conditions Cause Menstrual Blood Clots?

“Blood clots can be seen in normal cycles and typically are smaller than a quarter,” Crawford says. “However, some medical conditions can be associated with blood clots, including uterine fibroids, PCOS (if you have irregular periods especially), endometrial or cervical cancer, or an early unrecognized miscarriage.”

Williams adds that people with a condition called menorrhagia, or heavy menstrual bleeding, may experience more blood clots. She says this heavy flow should be evaluated by a healthcare professional to look for causes such as polyp, fibroids, adenomyosis, or endometriosis.

A hormone imbalance can also contribute to heavy menstrual bleeding and clotting.

When Should You Be Concerned?

Here are a few signs you need to see a doctor about menstrual blood clots, recommended by Crawford and Betsy Greenleaf, a board-certified ObGyn and female urogynecologist.

  • You’re bleeding heavily, to the point where you need to change your pad or tampon every hour or two.
  • You’re experiencing new-onset bleeding or blood clots while pregnant (if this happens, it’s important to see a doctor right away).
  • You notice a sudden change in your menstrual period—this could mean you’re bleeding more than usual, or the consistency of your menstrual fluid is different.
  • Your menstrual period is very painful.
  • Bleeding lasts more than seven days.
  • You feel dizzy, lightheaded, fatigued, or have shortness of breath while you’re on your period.
  • Your blood clots are larger than a quarter.
  • You’re passing large amounts of fleshy tissue.

Physicians say if your blood clots are small or infrequent, you probably don’t need to worry too much. But, “while one or two tiny clots—dime-sized or less—is generally considered normal, if they become larger or more numerous, it could indicate your flow may be too heavy, and you should see your gynecologist,” she adds.

The Takeaway

A small amount of menstrual blood is common and may not be a cause for concern—especially if they are a normal part of your cycle rather than something new, you’re not experiencing any other symptoms, and you’ve already discussed them with your doctor.

But sometimes, menstrual blood clots can warrant a visit to your gynecologist. If your clots are larger than a quarter or you’re experiencing any other signs or symptoms we mentioned above, it’s time to see your physician.

Even if your clots are small and you’ve never talked about them with your doctor before, it’s a good idea to bring them up at your next annual appointment to make sure everything is ok. Let your doctor know what’s going on, and they’ll be able to evaluate further if needed. As they say, it’s better to be safe than sorry.

QQ: Why Is My Period So Light?

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