Heavy periods are common, affecting roughly 1 in 10 women, and they usually point to a specific, treatable cause. Clinically, a period is considered heavy when you lose more than 80 mL of blood per cycle (about 5 to 6 tablespoons) or bleed for longer than 7 days. The tricky part is that most people with unusually heavy flow don’t realize it’s heavier than normal because they have no easy way to compare. Understanding what’s behind the bleeding is the first step toward fixing it.
How to Tell If Your Period Is Actually Heavy
Since you can’t measure blood loss at home in milliliters, practical signs matter more than numbers. Your period likely qualifies as heavy if you’re soaking through a pad or tampon every hour for several hours in a row, if you need to double up on protection (pad plus tampon), or if you’re waking up at night to change products. Passing blood clots larger than a grape is another reliable marker.
Other signs are less obvious but just as telling. Feeling exhausted, dizzy, or short of breath during or after your period can signal that you’re losing enough blood to become anemic. If your periods are limiting what you can do, canceling plans, or making you anxious about leaking, that alone is reason enough to investigate what’s going on.
Structural Causes: Fibroids, Polyps, and Adenomyosis
The most common physical reasons for heavy bleeding involve changes to the uterus itself. Fibroids are noncancerous growths in the uterine wall. They increase the surface area inside the uterus and can distort blood vessels, leading to heavier and longer periods. Polyps are smaller growths on the uterine lining that work similarly, creating extra tissue that sheds and bleeds each cycle.
Adenomyosis is a condition where tissue that normally lines the uterus grows into the muscular wall. It causes heavy bleeding in 40% to 60% of people who have it. The mechanism is straightforward: the uterine lining becomes thicker and more blood-vessel-rich, and the deeper the tissue invades, the heavier the bleeding tends to be. Adenomyosis also tends to cause significant cramping because the uterus has to work harder to shed that embedded tissue.
Hormonal Imbalances
Your period depends on a precise back-and-forth between estrogen and progesterone. Estrogen builds up the uterine lining in the first half of your cycle, and progesterone stabilizes it in the second half. When ovulation doesn’t happen (which can occur for many reasons), progesterone never kicks in, and the lining keeps thickening under estrogen’s influence alone. When it finally sheds, it does so irregularly and heavily.
Polycystic ovary syndrome (PCOS) is one of the most common causes of this pattern. High estrogen without enough progesterone lets the uterine lining build up excessively. The result is periods that are unpredictable, sometimes skipping months and then arriving with unusually heavy flow. Left untreated over time, this ongoing estrogen exposure can lead to abnormal thickening of the uterine lining, a condition called endometrial hyperplasia, which carries its own health risks.
Thyroid problems also disrupt the hormonal chain. Both an underactive and overactive thyroid can alter how your body regulates its menstrual cycle, making periods heavier, lighter, or irregular.
Bleeding Disorders and Medications
About 1 in 5 women with heavy periods has an underlying bleeding disorder that was never diagnosed. The most common is von Willebrand disease, where the blood doesn’t clot as efficiently as it should. If you’ve always had heavy periods starting from your very first one, bruise easily, or have prolonged bleeding after dental work or minor cuts, a clotting disorder could be the reason.
Certain medications also increase menstrual flow. Blood thinners are an obvious culprit, but copper IUDs (the non-hormonal type) commonly cause heavier periods, especially in the first few months after insertion. Anti-inflammatory medications taken regularly can affect platelets and contribute to heavier bleeding as well.
How Doctors Find the Cause
Expect your doctor to start with your history: how long your periods last, how often you change products, whether you pass clots, and how your cycle has changed over time. Keeping a brief diary of your flow for one or two cycles before your appointment makes this conversation more productive.
Blood tests come next. These check for iron deficiency anemia (the most immediate consequence of heavy bleeding), thyroid function, and clotting problems. A Pap test may be done to look for cervical changes. An ultrasound uses sound waves to create images of your uterus and ovaries, and it can reveal fibroids, polyps, or signs of adenomyosis.
If initial tests don’t give a clear answer, more targeted procedures follow. A sonohysterography involves filling the uterus with fluid during an ultrasound to get a clearer view of the lining. A hysteroscopy uses a thin, lighted camera inserted through the cervix to directly visualize the inside of the uterus. An endometrial biopsy takes a small tissue sample from the lining to check for abnormal or precancerous cells.
Treatment Options That Work
Treatment depends on the cause, but several options can significantly reduce bleeding regardless of the underlying reason.
For non-hormonal approaches, tranexamic acid is a medication taken only during your period that helps blood clot more effectively at the uterine lining. It reduces bleeding by about 40%. Anti-inflammatory medications taken during your period reduce flow by about 30% and help with cramping at the same time. Neither of these affects your hormones or fertility.
Hormonal treatments work by thinning the uterine lining so there’s less tissue to shed. A hormonal IUD is one of the most effective options, releasing a small amount of hormone directly into the uterus and dramatically reducing flow for most users. Combined birth control pills also reduce bleeding and regulate cycle timing. Research comparing the two has found both are effective at improving quality of life, though the IUD tends to reduce measured blood loss more. The best choice depends on whether you want the convenience of a set-and-forget device or prefer a daily pill you can stop at any time.
When structural problems like large fibroids or polyps are the cause, procedures to remove the growths or, in some cases, surgery may be recommended. These decisions are typically made after the less invasive options have been tried or when imaging clearly shows a problem that medication won’t resolve.
Protecting Yourself From Iron Loss
Heavy periods are the leading cause of iron deficiency in premenopausal women, and the symptoms (fatigue, brain fog, feeling cold, shortness of breath with mild activity) are easy to dismiss as stress or poor sleep. If your periods are heavy, assume your iron stores need attention.
Iron from red meat, fish, and poultry is the most easily absorbed form. Your body takes it up readily regardless of what else you eat in the same meal. Iron from plant sources like spinach, beans, oatmeal, dried apricots, and fortified cereals is absorbed much less efficiently on its own, but pairing these foods with something rich in vitamin C (orange juice, bell peppers, tomatoes, strawberries, broccoli) significantly boosts uptake. Even adding a small amount of meat to a bean-based meal improves absorption of the plant iron.
On the flip side, tea, coffee, and dairy products reduce iron absorption. If you’re actively trying to rebuild your iron levels, avoid drinking tea or coffee with iron-rich meals. Spacing out calcium-heavy foods from your main iron sources also helps.
Severe anemia from ongoing heavy periods can cause shortness of breath and increase the risk of heart problems. If you’re feeling winded climbing stairs or noticeably more fatigued than usual during your period, that’s worth bringing up with your doctor sooner rather than later.