A period that won’t stop is usually lasting longer than seven days, and the most common reason is a hormonal imbalance that prevents your body from producing the signal it needs to fully shed the uterine lining. A normal period lasts about four to five days with roughly two to three tablespoons of total blood loss. If yours stretches well past a week, or you’re soaking through a pad or tampon nearly every hour, something specific is driving it.
How Hormones Keep Bleeding Going
The single most common explanation for a period that drags on is that your body didn’t ovulate that cycle. Ovulation is the trigger that produces progesterone, and progesterone is what tells your uterine lining to stop thickening, organize itself, and shed cleanly. Without ovulation, progesterone never arrives. Estrogen keeps building the lining thicker and thicker with no counterbalance, and eventually that overgrown lining starts breaking down in uneven patches rather than shedding all at once. The result is bleeding that starts and stops unpredictably, or just never seems to end.
This kind of cycle is called anovulatory bleeding, and it’s especially common during puberty (when hormone patterns are still maturing), perimenopause, and in people with polycystic ovary syndrome. The excess estrogen also weakens the blood vessels in the uterine lining, making them more fragile and prone to heavier flow. So you don’t just bleed longer; you often bleed more.
Fibroids, Polyps, and Other Structural Causes
Sometimes the problem isn’t hormonal at all. Uterine fibroids are the most common structural cause of bleeding that won’t quit. These are noncancerous growths in the muscle wall of the uterus, and they interfere with bleeding in several ways: they increase the surface area of the lining, they disrupt the normal muscle contractions your uterus uses to clamp down on blood vessels after shedding, and they can compress veins inside the uterine wall, causing them to swell.
Endometrial polyps work differently. These are small, finger-like growths on the lining itself. They tend to bleed on their own schedule regardless of where you are in your cycle. Adenomyosis, a condition where uterine lining tissue grows into the muscular wall, can also keep periods going longer than expected and make them significantly heavier.
Thyroid Problems and Bleeding
An underactive thyroid can make your period last longer, and the connection isn’t obvious. Your thyroid hormones and reproductive hormones are regulated by overlapping systems in the brain, so when thyroid levels drop, it throws off the signals controlling your cycle. But hypothyroidism also directly changes how your blood clots. Low thyroid hormone shifts your body toward thinner blood that doesn’t clot as efficiently, partly by reducing levels of clotting proteins. In more severe cases, it can cause an acquired form of von Willebrand disease, a bleeding condition that resolves once thyroid levels are corrected with medication. If your long periods come with fatigue, weight gain, or feeling unusually cold, a thyroid issue is worth investigating.
Medications That Extend Your Period
Blood thinners are a well-recognized cause of heavier, longer periods. Anticoagulants prescribed for blood clots or heart conditions directly interfere with your body’s ability to stop bleeding anywhere, including the uterus. Among the commonly prescribed options, rivaroxaban appears to cause heavier menstrual bleeding more often than apixaban, dabigatran, or warfarin. If your period changed after starting any blood-thinning medication, that’s likely the connection.
Breakthrough Bleeding on Birth Control
If you recently started hormonal birth control and your bleeding won’t seem to stop, what you’re experiencing is probably breakthrough bleeding rather than an actual period. This is extremely common in the first three to six months of a new method.
With a hormonal IUD, about 35% of users deal with frequent or prolonged bleeding in the first six months. The good news: only 4% still have that problem after a year, and by 6 to 12 months, nearly half of IUD users stop getting periods altogether. With the implant, your bleeding pattern in the first three months tends to predict the rest of your experience. If it’s favorable early on, it usually stays that way. If it’s not, there’s roughly a 50% chance it improves on its own as your body adjusts to stable hormone levels.
What Testing Looks Like
If your period consistently runs past seven days or you’re bleeding heavily enough to soak through protection every hour, the first step is typically a transvaginal ultrasound. This is the standard starting point because it can identify fibroids, large polyps, and other structural issues without any invasive procedure. Ultrasound has limitations, though. It can’t always distinguish between polyps, certain types of fibroids, and adenomyosis. If something looks suspicious, a saline infusion sonography (where fluid is used to get a clearer view of the uterine cavity) or hysteroscopy (a thin camera inserted through the cervix) may follow.
Blood work is also part of the picture. Your provider will likely check thyroid function, iron levels (since prolonged bleeding often causes anemia), and possibly clotting factors. For anyone 45 or older, or if initial treatments aren’t working, an endometrial biopsy to rule out precancerous changes in the lining is generally recommended.
How Prolonged Bleeding Is Treated
Treatment depends entirely on the cause. If the problem is anovulatory bleeding, hormonal options like birth control pills, a hormonal IUD, or cyclic progesterone can provide the missing hormone signal and regulate shedding. For people who can’t or prefer not to use hormones, there’s a non-hormonal medication that helps your blood clot more effectively at the uterine lining. It’s taken only during your period and reduces blood loss by 26% to 60%, depending on the dose. It doesn’t shorten your cycle on its own, but it significantly cuts down the volume of bleeding.
If fibroids or polyps are identified, removing them often resolves the problem. For people who are done having children and haven’t responded to other treatments, endometrial ablation is an option. This procedure destroys the uterine lining to reduce or stop bleeding entirely. Thermal balloon ablation achieves normal bleeding patterns or no periods in about 92% of cases, with most people returning to daily activities within two to three days. Hysteroscopic ablation has a somewhat lower success rate (around 76%) but a slightly faster return to work.
If hypothyroidism is the culprit, correcting thyroid levels with medication typically resolves the bleeding changes, including reversing any acquired clotting issues that were making things worse.
Signs You Need Prompt Medical Attention
A period that runs a day or two long once in a while isn’t necessarily alarming. But soaking through a pad or tampon every hour for several consecutive hours is a sign of blood loss that can become dangerous. Other warning signs include passing clots larger than a quarter, feeling dizzy or lightheaded, or bleeding that has continued for more than two weeks. Prolonged heavy bleeding can cause iron-deficiency anemia, which brings its own symptoms: extreme fatigue, shortness of breath, and pale skin. If you’re experiencing any combination of these, getting evaluated sooner rather than later matters.