A normal period lasts about four to five days, with most people losing only two to three tablespoons of blood total. If your period regularly stretches beyond seven days, it’s considered prolonged and usually has an identifiable cause. The reasons range from harmless hormonal shifts to conditions worth treating, and figuring out which category you fall into starts with understanding what can make bleeding last longer than it should.
Growths Inside the Uterus
Two of the most common structural causes of long periods are uterine fibroids and uterine polyps. Polyps are small growths that attach to the inner wall of the uterus, either by a broad base or a thin stalk. They’re estrogen-sensitive, meaning they grow in response to estrogen circulating in your body. Fibroids are similar in concept but made of muscle tissue and can grow much larger. Both create extra surface area inside the uterus that bleeds during your period, and both can prevent the uterus from contracting efficiently enough to stop the bleeding on schedule.
The hallmark pattern with polyps and fibroids is heavy flow that drags on for days longer than it used to, sometimes with spotting between periods as well. Polyps are more likely to cause irregular, unpredictable bleeding, while fibroids tend to make periods progressively heavier over months or years. Neither is cancerous in the vast majority of cases, but both can worsen over time if left alone.
Adenomyosis
Adenomyosis is a condition where the tissue that normally lines the inside of your uterus grows into the muscular wall instead. During your period, that embedded tissue bleeds just like the lining does, but it has nowhere to drain efficiently. The result is heavy periods, clots, and bleeding that lasts well beyond a week. Many people with adenomyosis also experience intense cramping and a feeling of pressure or fullness in the lower abdomen.
Because the blood loss can be significant cycle after cycle, adenomyosis frequently leads to anemia. If you’ve noticed increasing fatigue, shortness of breath, or low energy alongside longer periods, the combination is worth mentioning to your doctor. Adenomyosis is most common in people in their 30s and 40s, and it’s often misdiagnosed or overlooked because its symptoms overlap with fibroids and endometriosis.
Hormonal Imbalances
Your period length is tightly controlled by the rise and fall of estrogen and progesterone. When that balance is off, the uterine lining can build up more than usual and then shed unevenly, leading to prolonged or unpredictable bleeding. This is especially common during two life stages: the first few years after periods start and the years leading up to menopause (perimenopause). In both cases, ovulation becomes irregular, which means progesterone levels drop and can’t do their job of organizing a clean, timely shedding of the lining.
Polycystic ovary syndrome (PCOS) is another frequent hormonal culprit. With PCOS, you may go weeks or months without ovulating, allowing the uterine lining to thicken excessively. When bleeding finally happens, it can be heavy and last much longer than a typical period.
Thyroid Problems
An underactive thyroid (hypothyroidism) has a surprisingly direct effect on your period. Low thyroid hormone changes how your blood clots, which can make bleeding harder to stop. It also causes the uterine lining to thicken excessively and then shed unpredictably. The result is periods that are both heavier and longer, sometimes accompanied by shorter cycles so it feels like you’re bleeding more often, too.
Thyroid issues are easy to detect with a simple blood test, and treating the underlying thyroid problem typically brings periods back to a normal pattern within a few months. If your long periods came on gradually alongside other symptoms like weight gain, fatigue, or feeling cold all the time, a thyroid check is a reasonable first step.
Bleeding Disorders
This is the cause most people don’t consider, but it’s more common than you’d think. Von Willebrand disease, a condition where your blood doesn’t clot properly, is found in roughly 13% of people investigated for unexplained heavy menstrual bleeding. That’s about one in eight. Many of these people have gone years without a diagnosis because heavy periods were dismissed as “just how their body works.”
Clues that a bleeding disorder might be involved include heavy periods that started from your very first cycle, a tendency to bruise easily, frequent nosebleeds, or prolonged bleeding after dental work or minor cuts. If this sounds familiar and no one has tested your clotting function, it’s worth asking about.
Your IUD Could Be the Cause
If you have a copper (non-hormonal) IUD and your periods got longer after insertion, you’re not imagining it. In a study of over 600 copper IUD users, 60% reported increases in menstrual blood flow and 50% reported more bleeding days over the first 12 months. This is one of the most well-documented side effects of the copper IUD, and for many users it improves somewhat after the first year but doesn’t fully resolve.
Hormonal IUDs, by contrast, typically make periods lighter and shorter over time. If your copper IUD is making your periods unmanageable, switching to a hormonal option or a different method entirely is a straightforward conversation to have with your provider.
How Long Periods Are Treated
Treatment depends entirely on the cause, which is why getting an accurate diagnosis matters more than jumping to solutions. For hormonal imbalances, hormonal birth control (pills, a hormonal IUD, or other methods) is often the first approach because it thins the uterine lining and regulates the cycle. Many people see their periods shorten to three or four days within a couple of months.
For fibroids or polyps, the approach depends on size and symptoms. Small polyps sometimes resolve on their own, while larger ones or fibroids causing significant bleeding can be removed through minimally invasive procedures. Adenomyosis is trickier since the tissue is embedded in the uterine wall, but hormonal treatments can manage the symptoms effectively for most people.
There are also non-hormonal medications that help reduce bleeding during your period by supporting your body’s clotting process. These are taken only during the days you’re actively bleeding and can make a noticeable difference in both flow and duration. For bleeding disorders like von Willebrand disease, treatment targets the clotting deficiency itself, which often resolves the period problem as a downstream effect.
Signs Your Bleeding Needs Urgent Attention
Most causes of long periods aren’t emergencies, but there’s a threshold where blood loss becomes a medical concern. If you’re soaking through two or more pads or tampons every hour for two to three hours in a row, that level of bleeding warrants same-day medical attention. Other red flags include passing clots larger than a quarter, feeling dizzy or lightheaded during your period, or a period that simply won’t stop after 10 or more days.
Even outside of emergencies, periods that consistently last more than seven days deserve investigation. A pelvic ultrasound, blood work checking your thyroid and iron levels, and sometimes a closer look inside the uterus can usually identify the cause. The fix is often straightforward once you know what you’re dealing with.