A normal period lasts about 4 to 5 days, and anything beyond 7 days is considered prolonged bleeding. If your period is stretching longer than usual, several things could be behind it, ranging from a one-off hormonal fluctuation to an underlying condition worth investigating. The cause often depends on your age, whether this is a new pattern or a recurring one, and how heavy the flow is.
What Counts as “Longer Than Usual”
Most periods fall in a 4-to-5-day window, with total blood loss of roughly 2 to 3 tablespoons across the entire cycle. Bleeding that extends past 7 days, or flow heavy enough that you’re soaking through a pad or tampon nearly every hour, crosses into what doctors classify as heavy menstrual bleeding. A period that runs 6 days when yours typically lasts 4 is probably not a concern on its own. But if the change persists over multiple cycles, or if the extra days come with noticeably heavier flow, that pattern is worth paying attention to.
Hormonal Shifts Are the Most Common Cause
Your menstrual cycle depends on a precise back-and-forth between estrogen and progesterone. Estrogen builds up the uterine lining in the first half of your cycle, and progesterone stabilizes it after ovulation. When you don’t ovulate in a given month (called an anovulatory cycle), progesterone never kicks in. Without it, the uterine lining keeps thickening under estrogen’s influence and doesn’t shed in a clean, predictable way. The result is often a period that drags on longer than normal, sometimes with irregular or heavier flow mixed in.
Anovulatory cycles happen to most people occasionally. Stress, illness, significant weight changes, intense exercise, and disrupted sleep can all suppress ovulation for a cycle or two. If this is the first time your period has run long and you’ve had a particularly stressful or physically demanding month, that’s a likely explanation. The next cycle often corrects itself.
Perimenopause and Age-Related Changes
If you’re in your late 30s or 40s, longer periods may signal the beginning of perimenopause. During this transition, estrogen levels rise and fall unpredictably rather than following their usual pattern. Ovulation becomes less reliable, which means some cycles produce plenty of progesterone and others produce very little. The practical effect is periods that shift in both directions: sometimes shorter and lighter, sometimes longer and heavier, sometimes skipped entirely.
Early perimenopause often shows up as cycles that vary by 7 or more days from month to month. Late perimenopause tends to involve gaps of 60 days or more between periods. A single longer-than-usual period in your 40s isn’t unusual, but bleeding that consistently exceeds 7 days still warrants a checkup even during this transition.
Growths in the Uterus
Uterine polyps are small, soft growths that develop on the inner lining of the uterus. They’re common, usually noncancerous, and one of the more frequent structural causes of prolonged bleeding. Because they create extra surface area of lining tissue, there’s simply more material to shed, and the process takes longer. Polyps can also bleed on their own between periods.
Fibroids are another possibility. These are muscular growths in the wall of the uterus that can distort its shape, interfere with the uterine lining’s ability to contract and stop bleeding efficiently, and increase menstrual flow. Both polyps and fibroids are typically detected through an ultrasound, and treatment depends on their size, location, and how much they’re affecting your quality of life.
Thyroid Problems
Your thyroid gland plays a surprisingly direct role in regulating your menstrual cycle. An underactive thyroid (hypothyroidism) is specifically linked to heavier-than-usual menstrual bleeding. An overactive thyroid can push periods in the opposite direction, making them lighter or causing them to disappear. Because thyroid issues develop gradually, they’re easy to miss. Fatigue, weight changes, feeling unusually cold, or changes in your skin and hair alongside longer periods could point to a thyroid issue. A simple blood test can confirm or rule it out.
Bleeding Disorders
This is the cause most people don’t think of, but it’s more common than you’d expect. Among women with chronic heavy menstrual bleeding, somewhere between 5% and 24% turn out to have an underlying bleeding disorder, most often von Willebrand disease. This condition affects how well your blood clots, and for many women, heavy or prolonged periods are the first and sometimes only symptom.
Clues that a bleeding disorder might be involved include periods that have always been heavy since your very first one, a tendency to bruise easily, prolonged bleeding after dental work or minor cuts, or a family history of bleeding problems. If that profile sounds familiar, it’s worth bringing up specifically, since routine gynecological exams don’t automatically test for clotting disorders.
Other Factors That Can Extend Bleeding
Certain IUDs, particularly the copper (non-hormonal) type, can make periods heavier and longer, especially in the first several months after insertion. Blood-thinning medications and even regular use of anti-inflammatory painkillers can affect how quickly bleeding stops. Infections of the uterus or cervix sometimes cause irregular or prolonged bleeding as well, often accompanied by unusual discharge, pelvic pain, or fever.
Signs That Need Prompt Attention
Prolonged bleeding isn’t life-threatening on its own, but over time it can lead to anemia, a drop in healthy red blood cells that leaves you feeling tired, weak, and short of breath. If you’re experiencing any of the following, it’s time to get evaluated sooner rather than later:
- Soaking through a pad or tampon every hour for several consecutive hours
- Fatigue, weakness, or shortness of breath that feels out of proportion to your activity level
- Bleeding between periods, even light spotting
- Periods that feel increasingly unpredictable in length and heaviness from one cycle to the next
Tracking your cycle length, flow, and symptoms for two or three months gives a doctor far more to work with than a vague report of “longer periods.” Note when bleeding starts, when it stops, how many products you go through per day, and any other symptoms. That information helps distinguish a hormonal blip from something that needs testing or treatment.