A normal period lasts between two and seven days. If yours is stretching past that mark, something is causing your uterine lining to shed more slowly or more heavily than it should. The reasons range from hormonal shifts and birth control side effects to structural changes in the uterus or, less commonly, an underlying bleeding disorder. Most causes are treatable once identified.
What Counts as a Prolonged Period
Clinically, a period lasting longer than seven days is considered prolonged, and bleeding that exceeds eight days falls into the category doctors call menorrhagia. But duration alone doesn’t tell the whole story. Menorrhagia is also defined by total blood loss exceeding 80 milliliters per cycle, which is hard to measure at home. A more practical gauge: if you’re soaking through a pad or tampon every hour for two or more hours in a row, or passing blood clots larger than a quarter, your bleeding is heavy enough to warrant medical attention.
There’s a simple tracking tool called the Pictorial Blood Loss Assessment Chart that can help you quantify what you’re experiencing. You score each pad or tampon based on how saturated it is: a lightly stained pad scores 1, a moderately soiled one scores 5, and a fully saturated pad scores 20. Tampons use a similar scale (1, 5, and 10). Small clots score 1, large clots score 5. A total score of 100 or higher across one cycle correlates with menorrhagia. Tracking even one cycle this way gives your doctor concrete information to work with.
Hormonal Imbalances
The most common reason for a period that drags on is a mismatch between estrogen and progesterone. Estrogen builds up your uterine lining each month; progesterone stabilizes it and triggers a clean, organized shed when its levels drop. When progesterone is too low relative to estrogen, the lining grows thicker than normal but sheds unevenly, leading to heavier, longer, and less predictable bleeding.
Polycystic ovary syndrome (PCOS) is one of the most frequent culprits. In PCOS, ovulation doesn’t happen reliably, which means progesterone levels stay low while estrogen continues to stimulate the uterine lining unopposed. The result is a lining that builds up excessively and then sheds in an irregular, drawn-out pattern. This also raises the risk of endometrial hyperplasia, a thickening of the uterine lining that can become a problem on its own if left unaddressed.
Thyroid disorders create a similar downstream effect. Both an underactive and overactive thyroid can disrupt the hormonal signals that regulate your cycle, making periods heavier, longer, or more erratic.
Your Age Matters
The likeliest explanation for a prolonged period shifts depending on where you are in your reproductive life.
In teenagers, the hormonal system that controls the menstrual cycle is still maturing, so irregular and sometimes prolonged periods are common in the first couple of years after menarche. But heavy, long periods in teens are too often dismissed as “just hormonal” when they may signal something more significant. Research from UT Southwestern Medical Center found that roughly 30 percent of young women evaluated for heavy periods were diagnosed with a previously unrecognized bleeding disorder. The three most common were von Willebrand disease (a genetic condition involving a missing or defective clotting protein), platelet disorders, and carrier status for hemophilia.
In women over 40, perimenopause is typically the driving factor. As ovarian function gradually declines, cycles become less predictable. You may skip ovulation some months, leading to the same unopposed-estrogen pattern seen in PCOS. Periods can become heavier, longer, closer together, or wildly irregular. That said, prolonged bleeding during perimenopause still deserves investigation, because structural causes like polyps and fibroids become more common with age.
Fibroids, Polyps, and Other Structural Causes
Uterine fibroids are noncancerous growths in the muscular wall of the uterus. They’re extremely common, and depending on their size and location, they can interfere with the uterus’s ability to contract efficiently during a period. Since those contractions are what helps stop bleeding and expel the lining, fibroids can extend bleeding for days beyond what’s normal.
Uterine polyps are softer growths that attach to the inner lining of the uterus by a base or a thin stalk. They can cause irregular bleeding, very heavy flow, and bleeding between periods. Both fibroids and polyps are typically detected with an ultrasound and can often be treated with minimally invasive procedures.
Birth Control Side Effects
Certain types of contraception are known to change bleeding patterns, sometimes dramatically. The copper IUD is one of the most common offenders. Because it doesn’t contain hormones, it doesn’t suppress the uterine lining the way hormonal methods do. Many copper IUD users experience heavier, longer, and more painful periods, along with spotting between cycles. These side effects typically improve within three to six months, but for some people they persist.
Progestin-only methods (the mini-pill, hormonal IUDs, the implant) can cause the opposite problem in a roundabout way: prolonged spotting or light bleeding that stretches across weeks, especially in the first few months of use. This isn’t a true period in the same sense, but it can feel like one that never ends. If your bleeding pattern changed after starting or switching birth control, that’s likely the connection.
Bleeding Disorders
An underrecognized cause of prolonged and heavy periods is an inherited bleeding disorder. The most common is von Willebrand disease, which affects the blood’s ability to clot properly. Among women with chronic heavy menstrual bleeding, estimates suggest 5 to 24 percent have an underlying bleeding disorder, according to the American College of Obstetricians and Gynecologists. Many go undiagnosed for years because heavy periods are often attributed to hormonal causes without further investigation.
Clues that a bleeding disorder might be involved include a history of easy bruising, prolonged bleeding after dental work or minor injuries, or a family history of bleeding problems. If these sound familiar, it’s worth asking specifically about clotting tests, since they’re not part of a standard workup.
How Prolonged Bleeding Affects Your Body
The most direct consequence of losing too much blood each cycle is iron deficiency anemia. Your body uses iron to produce the hemoglobin that carries oxygen in red blood cells, and heavy periods deplete those iron stores faster than most diets can replace them.
The symptoms can be subtle at first and easy to attribute to a busy life: extreme tiredness, weakness, feeling lightheaded or dizzy, a faster heartbeat, cold hands and feet. As anemia worsens, you might notice brittle nails, pale skin, headaches, or an inflamed tongue. Some people develop unusual cravings for ice, dirt, or other non-food items, a phenomenon called pica that’s a hallmark of significant iron deficiency. If you’ve been having long, heavy periods and any of these symptoms sound familiar, a simple blood test can confirm whether your iron levels are low.
How Prolonged Periods Are Treated
Treatment depends entirely on the cause, which is why getting a proper evaluation matters more than trying to manage symptoms on your own.
For hormonal imbalances, hormonal birth control (pills, hormonal IUDs, or other methods) is often the first-line approach because it regulates the buildup and shedding of the uterine lining. For people who can’t or prefer not to use hormones, there are non-hormonal options. Tranexamic acid is a medication taken only during your period that helps blood clot more effectively at the uterine lining. In clinical trials, it reduced menstrual blood loss by about 40 percent compared to a placebo. It’s taken for up to five days per cycle at the onset of heavy bleeding.
For structural causes like fibroids or polyps, the approach ranges from medication to manage symptoms to procedures that remove the growths. Many of these are outpatient, with recovery times measured in days rather than weeks.
For bleeding disorders, treatment is tailored to the specific condition. Von Willebrand disease, for example, can often be managed with medications that temporarily boost clotting factor levels during periods or before procedures.
If your period has been lasting more than seven days regularly, or if a single episode is significantly longer or heavier than your usual pattern, tracking your bleeding with the pad-scoring method described above gives you and your doctor a clear starting point for figuring out what’s going on.