What Causes Blood Clots During Your Period

Key Takeaways:

• Blood clots during menstruation are common and usually normal, caused by uterine lining shedding involving blood, tissue, and mucus, especially during heavy flow days.

• Hormonal imbalances and uterine growths like fibroids and polyps can lead to heavier periods and more noticeable blood clots, signaling potential health issues.

•  Conditions such as endometriosis and adenomyosis may result in larger or more frequent blood clots along with other symptoms like severe cramps and pain, where medical advice is often recommended.

In all honesty, periods have a way of throwing us curveballs, and one of the most common surprises is the appearance of thick, jelly-like clumps in your menstrual flow. If you’ve found yourself wondering, “What causes blood clots during my period?”, you are definitely not alone. In fact, many people will notice clots at some point in their lives, whether during particularly heavy flow days, right after childbirth, or even as your body’s hormones shift and change. While these clots can sometimes look concerning (and let’s face it, can often feel a bit messy or uncomfortable), they are usually a normal part of your cycle and your body’s way of handling menstrual bleeding.

At Saalt, we believe everyone deserves clear answers about their body, especially when those “is this normal?” questions pop up! Whether you’re in adolescence, navigating adulthood, or experiencing changes post-partum, understanding what’s happening with your period can help you feel more confident and in control. Cup for period collects clots and heavy flow in a hygienic seal—up to 12 hours leak-free, no mess. Pair with Saalt’s period panties for ultimate security, comfort, and confidence every day of your cycle. We’re here to give you the insights you need to understand your body’s signals and reassure you that you’re never alone. Let’s break it down together.

Are Period Blood Clots Normal or Not?

It’s totally valid to wonder if those jelly-like clumps in your menstrual flow are something to be concerned about. The truth is, blood clots during your period are actually quite common and, in most cases, completely normal. Here’s what’s really going on: your body sheds the lining of your uterus each month, and that process involves not only blood but also tissue and mucus. Sometimes, especially during heavier flow days, the blood pools in the uterus before leaving your body, giving it time to form clots.

For most people, these clots are small, about the size of a raisin or smaller, and show up at the heaviest part of your period. As your body’s natural anticoagulants (the compounds that help keep your blood from clotting too quickly) get overwhelmed by the volume, you’ll see those telltale clumps.

That said, not all clots are created equal. If you start seeing blood clots larger than a quarter, or if you’re soaking through pads or tampons every hour for multiple hours, it might be time to check in with your healthcare provider. Sometimes, frequent large clots can signal underlying issues like fibroids, polyps, or hormonal imbalances. Pay attention to how your period looks and feels, your body’s signals can help guide when you might need some extra support. Menstrual disc captures clots and heavy flow (up to 50ml+) in the fornix—no suction, discreet for 12hrs, ideal for messy cycles. (Cleveland Clinic)

How Menstrual Flow Creates Clots

Blood clots during your period might sound scary, but they’re typically just a part of your body’s natural process. When you have your period, the lining of your uterus sheds, this is what makes up most of your menstrual flow. This process involves a complex choreography between blood, tissue, and the body’s natural mechanisms to keep everything moving smoothly.

Here’s how it happens: as the uterine lining breaks down, the body releases blood, mucus, endometrial tissue, and other nutrients through the cervix and out of the vagina. Normally, anticoagulants, or enzymes that help thin the blood, are released to keep this flow as liquid as possible. But if your flow is coming out especially fast or is heavier than usual, your body sometimes can’t keep up with dissolving everything at the same time.

That’s when clots can form. These clumps are usually gel-like masses of blood and tissue, often ranging from a bright red to a darker brown. You might notice them more in the morning after lying down, or on heavier flow days. Menstrual cup collects clots and heavy flow (20-30ml capacity)—soft silicone seal catches everything mess-free for 12 hours. Larger clots (about the size of a quarter or bigger) or frequent clotting can sometimes signal an underlying health condition, but for the occasional clot, especially during heavy flow days, it’s all just part of your body’s way of managing your period.

Hormonal Imbalances That Trigger Clotting

Hormones play a starring role in almost every aspect of the menstrual cycle, dictating the flow, timing, and even the consistency of your period. When this delicate hormonal balance is thrown off, even just a little, it can lead to heavier periods, and with that, more noticeable blood clots.

Estrogen and progesterone are the main players. Estrogen thickens the uterine lining, prepping it for a potential pregnancy, while progesterone helps keep this process in check. When the balance between these two hormones is disrupted, whether due to puberty, perimenopause, stress, thyroid issues, or certain health conditions, your uterine lining can thicken more than usual. When your period starts and your body sheds this thicker lining, it can come out in larger pieces, resulting in blood clots.

Polycystic ovary syndrome (PCOS), thyroid disorders, and even major life changes like pregnancy or menopause can all cause fluctuations in hormone levels. The result? Periods that are heavier, longer, and more likely to involve clotting. Even erratic cycles or missed periods can be traced back to these same hormonal swings. Menstrual discs manage heavy, clotty flow (up to 50ml)—high fornix placement catches it all discreetly, sex-compatible, 12hr wear.

If you’ve noticed bigger or more frequent clots, or your cycles feel unpredictable, it may be a sign that your hormones are out of sync. Keeping tabs on your cycle and any changes you’re experiencing is key; this can help you and your healthcare provider pinpoint the root cause and get things back on track.

Fibroids, Polyps, and Other Uterine Growths

Sometimes, blood clots during your period can be traced back to changes within the uterus itself. Uterine fibroids, polyps, and other types of growths are much more common than you might think, and often go undetected until they start to impact your menstrual cycle.

Fibroids are non-cancerous growths composed of muscle and fibrous tissue that develop in or on the walls of the uterus. While many people with fibroids have no symptoms at all, others may notice heavier-than-usual periods accompanied by large clots. This happens because fibroids can increase the surface area of the uterine lining and disrupt normal blood flow, leading to heavier bleeding.

Polyps, on the other hand, are soft, fingerlike growths that form on the uterine lining (the endometrium). Like fibroids, they can cause heavier menstrual bleeding and the formation of blood clots, as well as spotting between periods. Menstrual cups flawlessly handle heavy, clotted flow (20-30ml)—secure wall seal contains messes for 12 hours leak-free.

There are also other, less common uterine growths, such as adenomyosis (where the tissue that normally lines the uterus grows into its muscular wall), that can create similar symptoms. These growths make it harder for the uterus to properly contract and shed its lining, sometimes resulting in the passage of larger clots.

If you’re noticing more frequent or larger blood clots during your period, or if your flow has suddenly gotten heavier, it’s a good idea to check in with your healthcare provider. Often, these growths can be managed with medication, minimally invasive procedures, or other treatment options tailored to your needs.

Endometriosis and Adenomyosis Explained

When talking about blood clots during your period, two medical conditions often come up: endometriosis and adenomyosis. Understanding these can help make sense of why you might be seeing thick, dark clots when you menstruate.

Endometriosis happens when tissue that’s similar to the lining of your uterus, the endometrium, starts growing outside the uterus, usually on the ovaries, fallopian tubes, or the tissue lining your pelvis. Each month, this tissue tries to shed just like the uterine lining does, but since it’s trapped outside your uterus, it can’t exit your body as it normally would. This often leads to severe cramps, pain, heavy bleeding, and, yes, bigger or more frequent blood clots. Period cup captures heavy clots and flow (up to 30ml)—soft seal, 12hr wear, no leaks even with endometriosis. (Web MD)

Adenomyosis, on the other hand, is when the endometrial tissue grows into the muscular wall of the uterus itself. Think of it like the lining of your uterus burrowing where it doesn’t belong. This can cause your periods to be heavier than usual, with a higher chance of clots, and can bring on a deep, achy pain that sometimes feels like your uterus is weighed down.

If you’re noticing sudden increases in heavy bleeding or more blood clots than you’re used to, or if your periods are just feeling way more painful and disruptive than before, it’s worth reaching out to a healthcare professional. These signs could be linked to conditions like endometriosis or adenomyosis, and getting the right diagnosis is key to reclaiming your comfort and peace of mind. (Mayo Clinic)

Understanding Your Flow and Taking Charge

Blood clots during your period can be unexpected, but for many people, they are a perfectly normal part of menstruation, especially during the heaviest days. These clots simply represent your body's natural way of shedding the uterine lining, aided by blood that can sometimes become thickened and pool before leaving the body. Period cups manage clots and heavy flow (20-30ml capacity)—hygienic seal contains everything mess-free for 12 hours, ideal for intense cycles. However, tracking your menstrual health is important. Frequent, very large clots, those larger than a quarter, or clots accompanied by unusual fatigue, pain, or heavy bleeding that soaks through products in under two hours could be a sign that your body needs extra attention. Conditions such as hormonal imbalances, fibroids, or other underlying issues can sometimes cause excessive clotting, so never hesitate to consult your healthcare provider if you have concerns.

At Saalt, our goal is to help you feel informed, empowered, and supported throughout your unique period experience. We believe that understanding what causes blood clots during your period is essential, not just for reassurance, but for taking proactive control over your health. That's why we offer sustainable, leakproof period care products, like comfortable, reusable underwear, that adapt to your cycles and provide peace of mind whether you’re out on an adventure or relaxing at home. Periods shouldn’t interrupt your life or confidence. By tuning in to your body and choosing supportive, planet-friendly products like period panties and leakproof panties that flawlessly wick moisture, absorb heavy flow/clots, and block leaks, you can embrace every day of your cycle with comfort and ease. Period panties, leakproof panties below flawlessly support all-day confidence. Remember, knowledge is power, and Saalt is here for you, every step along the way.

Read Also:

• How To Stop Blood Clots During Your Period Naturally

• What Period Products Are Best for Blood Clots?

• Large Period Clots: What They Mean and When to See a Doctor

Frequently Asked Questions About Blood Clots During Your Period

What are blood clots during a period?

Blood clots during your period are jelly-like lumps of partially coagulated blood mixed with tissue from your uterine lining. They can vary in size and color, usually appearing dark red or maroon. Passing a few small clots is totally normal for many people, especially during the heavier days of a cycle.

What causes blood clots to form during menstruation?

During your period, your body sheds the lining of the uterus. Normally, natural anticoagulants in your menstrual fluid prevent clotting. However, if your flow is especially heavy or quick, the blood can pool in the uterus and start to clot before it leaves your body. That’s why you might notice clots, even if nothing is wrong. Factors like hormonal changes, fibroids, or simply heavier flows can also play a role.

Does a heavy menstrual flow increase blood clotting?

Yes, a heavier menstrual flow can increase the likelihood of blood clots forming. When menstrual bleeding is heavier, the body’s natural anticoagulants can’t always keep up, so blood may clot as it pools in the uterus before exiting. Heavier periods can be influenced by stress, hormonal imbalances, postpartum changes, or certain health conditions.

Do I need to worry about large period blood clots?

Occasional small clots are usually just part of a normal period. However, if you’re regularly passing clots larger than a quarter, or experiencing a sudden increase in clotting, this might be your body asking for a check-in. It’s especially important to notice if clots are paired with severe cramps, dizziness, fatigue, or soaking through pads or leakproof underwear very quickly.

When should I see a doctor about period blood clots?

It’s time for a visit to your healthcare provider if you notice:

• Clots larger than a quarter happening frequently

• Needing to change your pad or leakproof underwear more than every 1-2 hours

• Severe cramps paired with heavy bleeding and clots

• Symptoms of anemia, like fatigue or shortness of breath

Remember, your period is unique to you. So if something suddenly feels off, it's always OK to ask for expert advice. At Saalt, we’re here to help you feel safe and supported through every stage, with premium, sustainable leakproof underwear designed for life’s leaks.

Sources:

1. Clinic, C. (2024, March 14). Period blood clots: Should you be concerned? Cleveland Clinic. https://health.clevelandclinic.org/period-blood-clots-are-they-normal

2. Endometriosis. (2025, November 26). Cleveland Clinic. https://my.clevelandclinic.org/health/diseases/10857-endometriosis

3. Heavy menstrual bleeding - Symptoms and causes. (n.d.). Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/menorrhagia/symptoms-causes/syc-20352829