A normal period lasts between 2 and 7 days, so if yours has stretched past that window, something has shifted in your body’s usual process. The causes range from completely benign (stress, a new contraceptive) to things worth investigating (hormonal imbalances, growths in the uterus). Most of the time, a single longer-than-usual period isn’t dangerous, but understanding the possible reasons helps you figure out whether to wait it out or get checked.
How Your Body Controls Period Length
Your period ends when your uterine lining finishes shedding and the blood vessels in the uterine wall clamp down and heal. That process depends on a precise hormonal sequence. After you ovulate, your body produces progesterone, which stabilizes the lining and, when it drops, triggers a clean, organized shed. If any part of that sequence gets disrupted, or if something physically prevents the lining from shedding evenly, bleeding drags on longer than it should.
Anovulation and Hormonal Imbalance
The most common hormonal reason for a longer period is a cycle where you didn’t ovulate. Without ovulation, your body never produces the progesterone surge that normally organizes the shedding process. Instead, estrogen keeps building up the uterine lining unopposed. That thicker, less stable lining doesn’t shed in a coordinated way. It breaks down irregularly, leading to bleeding that can last well beyond seven days and feel unpredictable in flow.
Anovulatory cycles happen to most people occasionally. Stress, illness, significant weight changes, over-exercising, and polycystic ovary syndrome (PCOS) are common triggers. You might notice the bleeding feels different too: lighter at times, then heavier, without the usual arc of heavy-to-light that a normal period follows. The high estrogen levels also weaken blood vessels in the lining, which can increase the overall volume of blood lost.
Perimenopause
If you’re in your 40s (sometimes late 30s), longer periods may signal the beginning of perimenopause. During this transition, estrogen and progesterone levels become erratic rather than following their usual monthly pattern. You may ovulate some months and skip others, which means some cycles produce plenty of progesterone and others don’t. The result is periods that vary wildly: shorter one month, longer the next, heavier, lighter, or skipped entirely.
This phase typically begins in the early-to-mid 40s and can last several years before menopause. It’s normal for periods to become longer or heavier during this time, but bleeding that consistently exceeds seven days or soaks through a pad or tampon every hour still warrants a closer look, because perimenopause can also unmask fibroids or other structural issues that become more common with age.
Fibroids and Polyps
Uterine fibroids (noncancerous muscle growths) and endometrial polyps (small tissue growths on the lining) are two of the most common structural causes of prolonged bleeding. They physically interfere with the uterus’s ability to shed its lining and contract back down.
Polyps are particularly interesting because they essentially don’t play by the same hormonal rules as the rest of your lining. Most polyps are made of immature tissue that doesn’t respond to your monthly hormone signals. While the surrounding lining sheds on schedule, the polyp stays put, and the congested blood vessels inside it can bleed on their own timeline. The polyp’s tissue also resists the normal cell turnover process that clears old lining, so it persists cycle after cycle, extending bleeding each time.
Fibroids, depending on their size and location, can distort the uterine cavity, increase the surface area of the lining, and prevent the uterine muscle from clamping down on blood vessels the way it normally does to stop bleeding. Submucosal fibroids (the kind that bulge into the uterine cavity) are the most likely to cause prolonged or heavy periods.
The Copper IUD
If you recently had a copper IUD placed, longer and heavier periods are one of the most predictable side effects. Research on copper IUDs shows they increase menstrual blood loss by about 50% compared to pre-insertion levels. In the first nine weeks after placement, about two-thirds of users report heavier bleeding. That proportion gradually drops, falling to about 48% after nine months, but the average number of bleeding days tends to hover around 5.5 to 6 days throughout the first year.
So if your period went from five days to seven or eight after getting a copper IUD, that’s a well-documented pattern. For most people, the heaviest and longest periods happen in the first few months and then slowly improve, though the increase in blood loss compared to your pre-IUD baseline may remain somewhat constant through at least the first year.
Thyroid Problems
Your thyroid gland plays a background role in regulating your menstrual cycle, and when it underperforms, your period often shows it. A study of reproductive-age women with hypothyroidism found that 65% of those with low thyroid hormone levels experienced heavy, prolonged periods. The severity of menstrual irregularities correlated with how elevated thyroid-stimulating hormone (TSH) levels were. The good news: thyroid hormone replacement therapy reduced menstrual blood loss in these women, suggesting the cycle disruption is reversible once thyroid function is corrected.
If your longer periods come alongside fatigue, weight gain, feeling cold, or brain fog, a thyroid issue is worth considering.
Bleeding Disorders
Some people have always had longer, heavier periods and assumed it was their normal. In some cases, an underlying bleeding disorder is responsible. Von Willebrand disease, the most common inherited bleeding disorder, affects the blood’s ability to clot efficiently. The uterine lining has a rich blood supply, so if your clotting system isn’t working at full capacity, it takes longer for bleeding to stop each cycle. If you also bruise easily, bleed a lot from dental work or cuts, or have family members with similar issues, this is worth mentioning to your doctor.
Signs That Need Prompt Attention
A period that runs a day or two long once isn’t usually an emergency. But certain patterns cross into territory where you should get evaluated sooner rather than later:
- Soaking through a pad or tampon every hour for several consecutive hours
- Passing blood clots the size of a quarter or larger
- Bleeding that lasts more than 7 days per period, especially if it’s a new pattern
- Symptoms of anemia like dizziness, shortness of breath, or extreme fatigue alongside heavy bleeding
Needing to change your pad or tampon more often than every two hours, or needing to double up on protection, is another signal that your blood loss has crossed from inconvenient into potentially problematic.
What to Expect at the Doctor
If you go in for prolonged bleeding, the first step is usually a pelvic ultrasound, which can reveal fibroids, polyps, or other structural issues. Blood work typically includes a complete blood count to check whether you’ve become anemic from the extra blood loss. If your symptoms suggest a thyroid problem, thyroid function tests may be added, though they aren’t a routine part of the workup for heavy bleeding alone.
If the ultrasound is inconclusive but your doctor suspects something inside the uterine cavity, a saline infusion sonography (where sterile fluid is used to get a clearer image of the cavity) or a hysteroscopy (a thin camera inserted through the cervix) may follow. For women 45 and older, or when initial treatments don’t work, an endometrial biopsy is often recommended to rule out precancerous changes in the lining.
How Prolonged Bleeding Is Managed
Treatment depends entirely on the cause. If anovulation is behind it, hormonal options like birth control pills or a hormonal IUD can provide the progesterone your body is missing, leading to thinner, more stable lining and shorter periods. For structural problems like polyps, removal during a hysteroscopy is straightforward and often solves the problem. Fibroids have a wider range of treatment options depending on their size and location.
For immediate relief from heavy, prolonged bleeding regardless of cause, a medication that helps blood clot more effectively at the uterine lining can reduce flow significantly. Anti-inflammatory pain relievers also reduce menstrual blood loss by about 20-40% and can shorten bleeding duration. Both are taken only during the days you’re actively bleeding, not throughout your cycle.
If a thyroid condition is identified, treating it with thyroid hormone replacement typically brings periods back toward their normal length and flow without any additional gynecologic intervention.