What Causes Heavy Periods? Common Reasons and Solutions

Key Takeaways:

• Common Signs Your Flow Is Heavier Than Average: Fast soak-through (under two hours), frequent doubling up, clots larger than a quarter, bleeding longer than seven days, or fatigue and dizziness can point to heavy menstrual bleeding worth tracking and discussing with a healthcare provider.
• Hormone Fluctuations, Nutrition, and Medication: Shifts in estrogen and progesterone can increase uterine lining buildup and raise flow volume. Lower iron stores can add fatigue and weakness during heavier cycles. In some cases, copper IUDs, anticoagulants, or other medications can also influence bleeding patterns.
• When Heavy Bleeding Signals Something More Serious: Persistent heavy bleeding can connect to fibroids, polyps, thyroid conditions, bleeding disorders, endometriosis, or adenomyosis. When symptoms feel outside your norm, medical guidance can help clarify causes and next steps.

Hearing “heavy period” rarely comes with a follow-up of support or straightforward answers. That gut-sinking moment can hit fast: checking your underwear in a bathroom stall, wondering if what you’re seeing is normal, or asking, “Why is my period so heavy this month?” Despite how common heavy period bleeding may be, many people carry the experience in silence, told to “deal with it” or worse, accept stress as part of the monthly routine.

At Saalt, we’re here to turn up the volume on honest, grounded period talk. We believe our cycles are not just something to manage, but something to understand, empowering us to advocate for our bodies and feel confident in our choices. Knowledge builds agency, and clarity matters when the question is, “What causes heavy periods?” Hormonal shifts, medications, uterine conditions, and lifestyle factors can all play a role in heavy menstrual bleeding, and each body’s pattern is valid.

From design-forward innovation in products to educational tools and an open, stigma-free community, we’re in this together. So, let’s get specific, break down the common causes of heavy periods, and offer solutions that put your comfort, agency, and the planet first. 

Common Signs Your Flow Is Heavier Than Average

Figuring out whether your period bleeding qualifies as "heavy" can feel confusing, especially since every body’s baseline is different. Here are some signs that your flow is heavier than what’s typical for most cycles:

• Frequent product changes: Needing to change your pad, cup, disc, or period underwear every hour for several hours in a row can point to heavy period bleeding.
• Double protection: Relying on two layers, like a cup with a backup pad or period underwear paired with a pad, may suggest your flow is above average.
• Overnight worries: Bleeding through products at night or waking up to change them can be a clue that flow is heavier than expected.
• Passing large clots: Clots larger than a quarter can point to a heavier cycle and deserve a check-in with a healthcare provider.
• Prolonged cycles: Periods lasting longer than a week, or soaking through multiple products across most of those days, can align with heavy menstrual bleeding.
• Activity disruption: Planning the day around bathrooms or feeling anxious about leaks at work, school, or the gym can signal that flow has crossed into “heavy.”
• Symptoms of anemia: Ongoing fatigue, weakness, dizziness, or shortness of breath during a period can connect to higher blood loss.

Noticing any of these signs? You’re not alone. Many people ask, “Why is my period so heavy all of a sudden?” and it’s valid to seek answers. Opening up about what you’re experiencing is the first step in making empowered, informed choices about your period care and health. In the meantime, menstrual cups and discs can provide reliable protection during heavier days.

Hormone Fluctuations and Their Impact on Menstrual Volume

When we ask, “Why is my period so heavy?” or “What causes heavy periods?” the answer often starts with hormones. Estrogen and progesterone are the body’s main conductors for regulating the menstrual cycle. When these hormones are in rhythm, most periods arrive with relative predictability and flow. But when the balance shifts, due to stress, puberty, perimenopause, certain medications, or even just the natural ups and downs of life, our flows can intensify.

Leading up to a period, estrogen helps thicken the uterine lining in preparation for a possible pregnancy. Progesterone helps keep that growth more controlled. When progesterone runs lower relative to estrogen, extra lining can build up. Once shedding starts, more tissue may release at once, which can lead to heavy menstrual bleeding. Shifts like stress, puberty, perimenopause, medication changes, or switching birth control can all influence that hormone balance.

On the medical side, conditions such as polycystic ovary syndrome (PCOS) or thyroid imbalances can intensify hormone swings. With PCOS, ovulation may happen less predictably, which can allow the uterine lining to keep building until the body sheds it later, sometimes as a heavier, longer bleed.

At the same time, hormone changes remain a common part of life across many stages. Tracking cycle patterns and noticing meaningful shifts can help guide next steps with a healthcare provider.

The Role of Medications, Including IUDs and Anticoagulants

If you’ve ever wondered why your period is so heavy, medications, blood thinners, and certain contraceptives may be influencing your flow.

In many cases, hormonal intrauterine devices (IUDs) can lighten periods over time. However, copper IUDs can have the opposite effect and may lead to heavy period bleeding, most commonly during the first few months after insertion. For many bodies, that increase settles as the uterus adjusts. For others, heavier bleeding can continue and may be worth discussing with a healthcare provider.

Another common factor involves anticoagulants, also known as blood thinners. These medications help treat or prevent blood clots, yet they can also increase bleeding and make periods feel heavier or last longer. When a dramatic change shows up after starting an anticoagulant, a clinician can help weigh options for managing symptoms safely.

Beyond IUDs and blood thinners, certain hormonal therapies and some over-the-counter medications can also affect flow. If you ever feel unsure whether a medication is affecting your period, talk with your healthcare provider. Together, you can find support and solutions that work for your body and your lifestyle. 

Nutrition, Iron Levels, and Menstrual Blood Loss

Anyone who's dealt with heavy period bleeding knows that it isn’t just about managing flow. Your body’s resources get tapped, too. One key nutrient tied to menstrual blood loss is iron. With heavier bleeding, iron stores can drop because iron leaves the body with blood. Fatigue, dizziness, weakness, or shortness of breath during a period can all connect to lower iron levels.

At the same time, nutrition influences how well the body replaces what’s lost. Diets low in iron, vitamin B12, or folate can make it harder to rebuild healthy blood levels after a heavy cycle. Over time, that pattern can contribute to iron-deficiency anemia, which happens when the body lacks enough red blood cells to carry oxygen where it’s needed.

For anyone managing heavy flows, tracking symptoms alongside nutrition can add useful context for a healthcare provider. In daily meals, iron-rich foods such as lentils, leafy greens, tofu, pumpkin seeds, dark chocolate, and fortified cereals can help replenish stores. Pairing plant-based iron with vitamin C sources like bell peppers, citrus, or strawberries can also boost absorption.

When exhaustion or dizziness feels persistent, reaching out for medical guidance can help confirm iron levels and identify what’s driving heavy menstrual bleeding. Over a few cycles, notes on flow, energy, and food patterns can make conversations with a provider clearer and more productive. For day-to-day protection, period underwear can help reduce leak stress during heavier days.

When Heavy Bleeding Signals Something More Serious

We know that periods can look different for everyone. Some cycles are light and easy; others feel like they could power a small waterfall. But heavy period bleeding, also called menorrhagia, is something your body might be trying to flag for your attention. Here are some signs to look out for.

Signs That Deserve a Closer Look

Certain patterns suggest blood loss may be outside your normal range. In those moments, support and answers matter.

• Soaking through protection quickly: Bleeding through a pad, tampon, cup, disc, or period underwear in under two hours, repeatedly, can point to heavy flow that needs attention.
• Needing to double up often: Relying on two layers, like a cup plus a backup pad or period underwear plus a pad, may signal that flow has shifted into heavier territory.
• Passing large clots: Clots larger than a quarter can happen with heavier cycles and deserve a check-in if they show up consistently.
• Bleeding longer than a week: Periods that stretch beyond seven days, or stay intensely heavy for several of those days, can connect to underlying causes.
• Feeling drained or lightheaded: Fatigue, dizziness, shortness of breath, and weakness can be signs you’re losing too much blood during period. If these symptoms persist, seeking medical care should be your top priority.

Common Reasons Heavy Bleeding Can Happen

Many causes are treatable, and a clinician can help narrow down what fits your symptoms and health history.

• Hormonal imbalances: Shifts in estrogen and progesterone can change how much uterine lining builds, which can lead to heavier, longer bleeding.
• Fibroids and polyps: These benign growths in the uterus can increase menstrual volume and may cause flooding, clots, or longer cycles.
• Bleeding disorders: Conditions such as von Willebrand disease can affect clotting and lead to heavier bleeding than expected.
• Endometriosis or adenomyosis: Tissue growing where it shouldn’t can make periods heavier and often adds more pain, pelvic pressure, or deep cramping.
• Thyroid conditions: An overactive or underactive thyroid can disrupt cycle regulation and contribute to heavier or more irregular bleeding.
• Certain medications: Blood thinners and some contraceptives can influence flow and make bleeding heavier for some bodies.

Support While You Seek Answers

When heavy bleeding affects daily life, medical guidance can help clarify what’s driving the change and what treatment options make sense. At the same time, practical protection can ease the day-to-day stress while patterns get tracked. For anyone looking for internal options during heavier days, our period discs can offer reliable coverage. Need help with inserting your cup or disc? Learn with our step-by-step guide on how to insert menstrual disc. 

Make The Switch

Heavy period bleeding can feel isolating, but you’re far from alone in asking, “Why is my period so heavy?” There are real answers rooted in biology, like hormonal shifts, underlying health conditions, and even the way our bodies naturally ebb and flow across the years. Instead of struggling through in silence, we believe in opening the conversation and reclaiming our agency.

At Saalt, we’re committed to uplifting every person navigating their menstrual health. Your period deserves respect and carefully engineered solutions that honor both your body and the planet. Our reusable cups, discs, and period underwear are high-performance, leak-proof, and body-safe. Listen to your body, ask questions, and don’t shy away from seeking support when you need it. Together, we can break taboos, build a more sustainable world, and create a future where you feel confident.

Frequently Asked Questions About Heavy Periods and What Causes Them

Is endometriosis a reason for heavy menstrual flow?

Yes. Endometriosis can absolutely be behind heavy period bleeding. This condition happens when tissue similar to the uterine lining grows outside the uterus, often causing inflammation and pain during menstruation. That can lead to heavier, longer periods with clots or intense cramping along the way. If you suspect endometriosis, talk to your healthcare provider. 

Could polyps in the uterus lead to heavy periods?

Uterine polyps are small, soft growths on the inner wall of the uterus. While benign, they can make periods heavier or more prolonged. Some people notice bleeding between periods, too. Polyps are treatable, so if your period suddenly changes, it’s worth getting checked out.

Are fibroids linked to heavy menstruation?

Yes. Uterine fibroids, non-cancerous muscular growths in the uterus, are a common cause of heavy or prolonged periods. You might also notice pelvic pressure or even discomfort during sex. Fibroids are nothing to be embarrassed about; they’re incredibly common, and there are a range of solutions available.

How do bleeding disorders affect menstruation?

Bleeding disorders like von Willebrand disease or platelet function disorders interfere with the body’s ability to clot blood effectively, leading to heavier or prolonged bleeding during menstruation (National Hemophilia Foundation). If you consistently soak through pads, cups, or period underwear, or bleed for more than a week, it’s a good idea to ask your provider about testing.

Can thyroid problems result in heavy periods?

Both underactive (hypothyroidism) and overactive (hyperthyroidism) thyroid conditions can directly affect your period flow. They impact hormone balance, sometimes leading to heavier, irregular, or even missed menstrual cycles. Thyroid issues can come with other symptoms, like fatigue or changes in weight, so pay attention to what your body’s telling you.

Can pelvic infections contribute to heavy periods?

Pelvic infections, like pelvic inflammatory disease (PID), can inflame reproductive organs, causing more bleeding during menstruation. Other possible symptoms: pelvic pain, unusual discharge, or even fever. If you notice these alongside a change in your periods, prompt medical attention.

Are certain cancers associated with heavy menstrual bleeding?

Yes. Cancers of the reproductive system (like uterine, cervical, or ovarian cancers) sometimes cause abnormal or unexpectedly heavy periods. While cancer is a rare cause, it’s important to listen to your body and flag any persistent changes with your healthcare provider. Early detection is powerful.

Can lifestyle factors influence period heaviness?

Definitely. High stress, changes in body weight, being over- or under-exercised, and certain medications can all impact hormone levels, sometimes resulting in a heavier period. Even environmental factors, from what’s in our water to toxins in synthetic products, can play a role.

Sources:

1. Centers for Disease Control and Prevention. (2024, May 7). Healthy habits: Menstrual hygiene. U.S. Department of Health & Human Services. https://www.cdc.gov/hygiene/about/menstrual-hygiene.html
2. Physicians Committee for Responsible Medicine. Using foods against menstrual pain. https://www.pcrm.org/good-nutrition/nutrition-information/using-foods-against-menstrual-pain
3. Cleveland Clinic. (2025). Irregular periods (abnormal menstruation): Causes and treatment. https://my.clevelandclinic.org/health/diseases/14633-abnormal-menstruation-periods
4. Mayo Clinic. (2023, August 30). Heavy menstrual bleeding (menorrhagia): Symptoms and causes. https://www.mayoclinic.org/diseases-conditions/menorrhagia/symptoms-causes/syc-20352829
5. National Hemophilia Foundation. Von Willebrand disease. https://www.bleeding.org/bleeding-disorders-a-z/types/von-willebrand-disease