A period lasting 14 days is twice the upper limit of what’s considered normal, and it signals that something is disrupting your body’s usual process of shedding and stopping. Normal menstrual bleeding lasts 2 to 7 days. Bleeding beyond 7 days is clinically classified as prolonged, and at 14 days, there’s almost certainly an underlying cause worth identifying.
The good news is that most causes are treatable. The key is figuring out which one applies to you, because the list ranges from hormonal imbalances to structural issues inside the uterus to side effects from contraception.
How a Normal Period Ends (and Why Yours Isn’t)
During a typical cycle, you ovulate around day 14, and your body produces progesterone afterward. Progesterone stabilizes the uterine lining and, when it drops roughly two weeks later, triggers a controlled shedding: your period. The lining comes away evenly, blood vessels constrict to slow bleeding, and clotting factors seal things off within a week.
A 14-day period means one or more of those steps is failing. Either the lining grew too thick to shed efficiently, the hormonal signals that stop bleeding aren’t arriving on time, or something physical inside the uterus is preventing the blood vessels from closing properly.
Anovulation and Hormonal Imbalance
The most common reason for prolonged bleeding in people of reproductive age is anovulation, meaning your ovaries didn’t release an egg that cycle. Without ovulation, your body doesn’t produce progesterone. Estrogen continues building up the uterine lining unopposed, and it keeps thickening well beyond what a normal cycle would produce. When that overgrown lining finally breaks down, it doesn’t shed in the neat, organized way a progesterone-regulated lining does. Instead, it comes away in patches over many days, sometimes weeks.
Polycystic ovary syndrome (PCOS) is the leading cause of chronic anovulation. But you can also have occasional anovulatory cycles from stress, significant weight changes, overexercise, or perimenopause. If your periods are also irregular in timing (coming every 40 or 50 days, or skipping months), anovulation is a strong possibility.
Fibroids and Polyps
Uterine fibroids are noncancerous muscle growths in the wall of the uterus. When they develop near the inner lining, they increase the surface area that bleeds during a period and physically interfere with the uterus’s ability to contract and clamp down on blood vessels. That means bleeding takes longer to stop.
Endometrial polyps are softer growths that form directly on the uterine lining. They range from the size of a sesame seed to the size of a golf ball. Polyps have their own blood supply and can bleed independently of the rest of the lining, extending your period well past its natural endpoint. Both fibroids and polyps are extremely common, and most people don’t know they have them until prolonged or heavy bleeding prompts an ultrasound.
Thyroid Problems
Your thyroid controls the pace of many bodily processes, and menstruation is one of them. An underactive thyroid (hypothyroidism) slows things down in ways that directly affect your period: it changes how your blood clots, making it harder for your body to stop bleeding efficiently, and it can cause the uterine lining to thicken excessively and then shed unpredictably. The result is periods that are heavier, longer, or both. Thyroid disorders are often missed because symptoms like fatigue, weight gain, and feeling cold overlap with so many other conditions, but a simple blood test can identify the problem.
Copper IUD and Contraception Changes
If you recently had a copper IUD inserted, prolonged and heavy periods are a well-documented side effect, particularly in the first few months. The copper creates a local inflammatory response inside the uterus that intensifies bleeding and cramping. For most users, this settles down over three to six months, but some people continue to experience longer periods for as long as the device is in place.
Hormonal contraceptives can also cause prolonged bleeding, though in different ways. Starting, stopping, or switching birth control pills, patches, or hormonal IUDs can trigger weeks of breakthrough bleeding while your body adjusts. This is usually temporary, but bleeding that persists beyond three months of a new method is worth investigating.
Less Common but Serious Causes
Bleeding disorders that affect clotting, such as von Willebrand disease, can cause periods that won’t stop on schedule. These conditions are often present from the very first period but go undiagnosed for years because heavy bleeding gets normalized. Infections of the uterus or cervix can also cause prolonged bleeding, typically accompanied by unusual discharge, pelvic pain, or fever.
Endometrial hyperplasia, a precancerous thickening of the uterine lining, is another possibility, particularly for people over 35 who have been having irregular cycles for a long time. Rarely, prolonged bleeding is a sign of uterine or cervical cancer. The risk is low, especially in younger people, but it’s one of the reasons a 14-day period warrants proper evaluation rather than just waiting it out.
What to Expect at the Doctor’s Office
When you describe a 14-day period, your provider will typically start with blood work to check for iron deficiency anemia (which prolonged bleeding can cause), thyroid dysfunction, and clotting problems. An ultrasound is the standard imaging tool for spotting fibroids, polyps, and other structural abnormalities inside the uterus.
If the ultrasound doesn’t reveal a clear answer, additional steps may include a sonohysterogram (where fluid is injected into the uterus to give a more detailed picture of the lining) or a hysteroscopy, where a thin camera is inserted through the cervix to look directly inside. An endometrial biopsy, which takes a small tissue sample from the lining, is used to rule out precancerous or cancerous changes, especially in people over 35 or those with long histories of irregular bleeding.
Why Anemia Is the Immediate Concern
While you’re working toward a diagnosis, the most pressing physical risk of a 14-day period is iron loss. Your body loses iron with every day of bleeding, and two weeks of blood loss can deplete your stores quickly. Symptoms of iron deficiency anemia include extreme tiredness, weakness, pale skin, dizziness, a fast heartbeat, shortness of breath with minimal effort, cold hands and feet, and brittle nails. Some people develop unusual cravings for ice, dirt, or other non-food items.
If you’re experiencing any of these alongside your prolonged period, it’s worth asking for an iron panel as part of your initial blood work. Iron deficiency is both the most common complication of prolonged bleeding and the most straightforward to treat, but it won’t resolve on its own if the bleeding continues cycle after cycle.