A normal period lasts between 2 and 7 days. If yours is stretching past that window, something is likely disrupting the usual hormonal signals that tell your uterine lining to stop shedding. The causes range from completely benign (a stressful month, a new IUD) to conditions worth investigating with your doctor (hormonal imbalances, thyroid problems, or growths in the uterus). Here’s what could be going on.
How Your Period Normally Stops
Your period is the shedding of your uterine lining, and it’s controlled by a back-and-forth between two hormones: estrogen and progesterone. Estrogen builds the lining up each month; progesterone keeps that growth in check and helps the lining shed in an organized way after ovulation. When both hormones drop at the end of a cycle, bleeding starts, and it typically wraps up within a week because there’s only so much lining to shed.
When this system works smoothly, your body builds a moderate-thickness lining, sheds it efficiently, and moves on. Prolonged periods almost always trace back to something interfering with that process: too much lining built up, trouble shedding it, or a problem with clotting that keeps the bleeding going.
Hormonal Imbalances
The most common reason for a period that drags on is an imbalance between estrogen and progesterone. If your body produces too much estrogen relative to progesterone, a situation sometimes called “unopposed estrogen,” the uterine lining grows thicker than normal. A thicker lining takes longer to shed, which means more days of bleeding and often a heavier flow.
This imbalance can happen for a number of reasons. Stress, significant weight changes, and sleep disruption all affect hormone production. Carrying extra body fat increases estrogen levels because fat tissue actively produces estrogen. Even a single unusually stressful month can delay ovulation or suppress progesterone enough to change your period’s length.
Skipped Ovulation
If you didn’t ovulate during a cycle, your body never produces the progesterone surge that normally follows ovulation. Without progesterone to regulate the lining, estrogen keeps building it up unchecked. When the lining eventually breaks down, the bleeding can be irregular, prolonged, and heavier than usual. This type of bleeding isn’t technically a true period. It’s sometimes called anovulatory bleeding.
Polycystic ovary syndrome (PCOS) is one of the most common causes of skipped ovulation. PCOS causes excess androgens (sometimes called “male hormones,” though everyone has them), which prevent the follicles in the ovaries from maturing enough to release an egg. The result is cycles that are unpredictable in both timing and duration. If your long period also came after a longer-than-usual gap between cycles, anovulation is a strong possibility.
Uterine Fibroids and Polyps
Fibroids are muscular growths in or on the uterus. Polyps are softer growths that form on the inner uterine wall from an overgrowth of endometrial cells. Both are extremely common and usually noncancerous, but both can cause periods that last longer, bleed heavier, or produce spotting between cycles.
Polyps are estrogen-sensitive, meaning they grow in response to estrogen. They increase the surface area of the lining and can interfere with the uterus’s ability to contract and seal off blood vessels after shedding, which is one of the key mechanisms your body uses to stop a period. Fibroids, especially those that grow into the uterine cavity, cause similar problems. They distort the lining, increase its surface area, and make it harder for the uterus to clamp down and stop bleeding.
Adenomyosis
Adenomyosis happens when tissue that normally lines the uterus starts growing into the muscular wall of the uterus itself. This causes the uterus to enlarge and makes periods heavier, longer, and more painful. It’s frequently found alongside fibroids and endometriosis, which can make it tricky to diagnose since the symptoms overlap. If your prolonged period also comes with intense cramping and a feeling of heaviness or pressure in your pelvis, adenomyosis is worth asking about.
Thyroid Problems
Your thyroid gland plays a behind-the-scenes role in regulating your menstrual cycle. An underactive thyroid (hypothyroidism) can prolong periods through multiple pathways at once. It disrupts the hormonal signals that control your cycle, and it also shifts your blood’s clotting ability toward a state where clots form less efficiently. That means once bleeding starts, your body is slower to stop it. If you’re also experiencing fatigue, weight gain, feeling cold all the time, or brain fog alongside your long period, a thyroid check is a reasonable next step.
Bleeding Disorders
Some people bleed longer simply because their blood doesn’t clot as well as it should. Von Willebrand disease is the most common inherited bleeding disorder, and it’s significantly underdiagnosed in women. Among women with chronic heavy or prolonged periods, between 5% and 24% turn out to have von Willebrand disease. The prevalence appears to be higher in white women (around 16%) compared to Black women (around 1%).
Clues that a bleeding disorder might be involved include a history of easy bruising, prolonged bleeding after dental work or surgery, frequent nosebleeds, or a family history of bleeding problems. Many women with these disorders assume their heavy, long periods are just “normal for them” because they’ve always been that way.
IUDs and Contraception Changes
If you recently got a copper IUD, longer and heavier periods are a well-documented side effect. Copper IUDs can increase menstrual flow by 25% to 50%, and the first two to three cycles after insertion tend to be the worst. This usually settles down over the following months, but for some people the heavier bleeding persists.
Starting or stopping hormonal birth control can also cause prolonged bleeding. When you stop the pill or another hormonal method, your body needs time to re-establish its own hormonal rhythm. The first few cycles off birth control are often irregular in both timing and duration. Similarly, switching to a new hormonal method can cause extended spotting or bleeding as your body adjusts, sometimes for up to three months.
Perimenopause
If you’re in your late 30s or 40s, perimenopause is one of the most likely explanations. During this transition, estrogen and progesterone levels rise and fall unpredictably rather than following the steady monthly pattern of earlier years. You may skip ovulation some months, which leads to the same thickened-lining, prolonged-bleeding pattern described above. Periods can become longer, shorter, heavier, lighter, closer together, or further apart, sometimes changing from one cycle to the next. This phase can last several years before periods stop entirely.
When Prolonged Bleeding Is a Red Flag
A period that runs a day or two past your usual length after a stressful month is rarely cause for alarm. But certain patterns deserve prompt attention. Soaking through a pad or tampon every hour for more than two consecutive hours is a sign of blood loss that can lead to anemia. Passing blood clots larger than a quarter also signals excessively heavy flow. If your period consistently lasts more than 7 days, or if you’re experiencing fatigue, dizziness, shortness of breath, or pale skin alongside the prolonged bleeding, those are signs your body may be losing more blood than it can comfortably replace.
How Prolonged Periods Are Treated
Treatment depends entirely on the underlying cause, but there are a few common approaches. For hormonal imbalances and anovulatory bleeding, hormonal treatments that supply progesterone or regulate the cycle are often the first step. These work by thinning the uterine lining so there’s simply less tissue to shed.
For immediate symptom relief, anti-inflammatory medications like ibuprofen can modestly reduce menstrual blood loss. A prescription medication that helps blood clot more effectively has been shown to reduce bleeding by roughly 73 mL per cycle compared to anti-inflammatory drugs alone. For fibroids or polyps that are clearly causing the problem, removal procedures are an option and often resolve the bleeding quickly. Thyroid disorders are treated by correcting the thyroid hormone levels, which typically normalizes periods within a few cycles. Bleeding disorders are managed with targeted therapies that improve clotting.
The most useful thing you can do right now is start tracking your cycles if you aren’t already. Note how many days you bleed, how heavy the flow is (light, moderate, heavy, or soaking-through), and any other symptoms like pain, fatigue, or mid-cycle spotting. That information makes it much easier for a provider to narrow down the cause quickly rather than running through a long list of possibilities.