A normal period lasts 4 to 5 days, and anything beyond 7 days is considered clinically prolonged. If your period has stretched to two weeks, something is disrupting the normal process of building up and shedding your uterine lining. The cause is usually identifiable and treatable, but it’s worth understanding what might be behind it.
How Your Cycle Normally Stops Bleeding
Each month, your body goes through a hormonal sequence. After ovulation, a temporary structure in the ovary called the corpus luteum pumps out progesterone for about 14 days. Progesterone thickens and stabilizes the uterine lining. If no pregnancy occurs, the corpus luteum breaks down, progesterone and estrogen both drop, and the top layers of the lining shed in a controlled way over 4 to 5 days. The total blood loss is small, roughly 2 to 3 tablespoons.
When any part of this sequence goes wrong, the lining either builds up too much before shedding, sheds unevenly, or never gets the hormonal signal to stop. That’s what turns a few days of bleeding into a week or two.
Hormonal Imbalance Is the Most Common Cause
The most frequent reason for a two-week period is a disruption in the balance between estrogen and progesterone. If you don’t ovulate during a cycle (called an anovulatory cycle), your body never produces the progesterone surge that would normally stabilize the lining. Estrogen keeps thickening it unchecked, and eventually the lining outgrows its blood supply and starts breaking down in patches rather than all at once. The result is prolonged, irregular bleeding that can drag on for weeks.
Anovulatory cycles happen to most people occasionally, especially during times of change like puberty, postpartum, or the years leading into menopause. But if they happen frequently, there’s usually an underlying reason.
PCOS and Irregular Ovulation
Polycystic ovary syndrome is one of the most common causes of chronic anovulation in people of reproductive age. In PCOS, higher-than-normal levels of androgens interfere with the hormonal signals needed to trigger ovulation. Without ovulation, progesterone stays low, and the uterine lining continues to build. When it finally sheds, it does so unpredictably, sometimes producing prolonged bleeding after weeks or months of no period at all.
If your periods swing between being absent for long stretches and then lasting well beyond a week, PCOS is a strong possibility. Other signs include acne, excess facial or body hair, and difficulty maintaining a stable weight. An ultrasound can check both the ovaries and the thickness of the uterine lining, which is often a key part of the workup.
Thyroid Problems
Your thyroid gland has a surprisingly strong influence on your menstrual cycle. An underactive thyroid (hypothyroidism) suppresses a brain hormone called gonadotropin-releasing hormone, which your ovaries need to function properly. It also raises prolactin levels, which in turn lowers estrogen and disrupts cycle regularity. Studies have found that anywhere from 23% to 68% of people with hypothyroidism experience irregular menstrual cycles, and some experience heavier, longer bleeding because thyroid hormone deficiency changes how blood clots and allows the uterine lining to thicken excessively.
A simple blood test can check your thyroid function, and treating hypothyroidism often resolves the bleeding issues along with other symptoms like fatigue, weight gain, and cold sensitivity.
Stress and Cortisol
Chronic stress raises cortisol, your body’s main stress hormone. When cortisol stays high, it essentially overrides your reproductive hormones. The body deprioritizes reproduction when it senses danger, even if that “danger” is workplace burnout or caregiving exhaustion. Both estrogen and progesterone drop, ovulation becomes unreliable, and the result is irregular cycles that can include prolonged or heavy bleeding.
This isn’t just about a stressful week. Short-term stress might delay your period by a few days. It’s sustained, months-long stress that tends to produce the kind of hormonal disruption that leads to a two-week bleed. If your period changed around the same time your stress levels spiked, that connection is worth paying attention to.
Perimenopause
If you’re in your 40s (or sometimes late 30s), perimenopause is a likely explanation. As the ovaries gradually produce less consistent hormones, ovulation becomes unpredictable. Some cycles are shorter, some are longer, flow varies from light to heavy, and periods that stretch well past a week become more common. An early sign of perimenopause is when your cycle length starts varying by 7 or more days from what’s normal for you.
Prolonged bleeding during perimenopause is common but shouldn’t be ignored, particularly because the risk of other causes like polyps and abnormal lining changes increases with age. Bleeding that lasts longer than 7 days or occurs between periods warrants evaluation even if perimenopause seems like the obvious explanation.
Fibroids and Polyps
Structural growths in the uterus can physically interfere with the lining’s ability to shed cleanly and the uterine muscles’ ability to contract and stop bleeding. Uterine fibroids are noncancerous muscle growths in or on the uterine wall. Endometrial polyps are smaller growths that form in the lining itself. Both can cause periods that are heavier, longer, or both.
These growths are extremely common. Fibroids affect the majority of women by age 50, though many cause no symptoms. When they do cause prolonged bleeding, location matters more than size. A small fibroid pressing into the uterine cavity can cause worse bleeding than a large one on the outer wall. Polyps similarly vary in impact, but because they sit directly in the lining, they tend to cause bleeding between periods or extended periods.
New Birth Control
Starting a new hormonal contraceptive, particularly an IUD, is a well-known trigger for prolonged or irregular bleeding. With hormonal IUDs, breakthrough bleeding and spotting are common in the first three months while the body adjusts. The same applies to birth control pills, implants, and injections, especially if you’ve recently switched methods or started one for the first time.
This type of bleeding is usually lighter than a true period, more like persistent spotting, and it typically resolves on its own within three months. If it continues beyond that, or if the bleeding is heavy rather than light, your contraceptive method may need to be reassessed.
Signs That Need Prompt Attention
A two-week period always warrants a conversation with a healthcare provider, but certain patterns signal more urgency. Soaking through a pad or tampon every hour for several hours in a row is considered a red flag. So is passing blood clots the size of a quarter or larger, needing to double up on pads, or having to change protection during the night. If the bleeding is heavy enough to interfere with your normal daily activities, that alone qualifies as abnormal.
Prolonged heavy bleeding can lead to iron deficiency anemia, which shows up as fatigue, dizziness, shortness of breath, and pale skin. If you’ve been bleeding for two weeks and feel noticeably run down, that’s your body telling you it’s losing more blood than it can easily replace.
What to Expect at the Doctor
When you describe a two-week period, your provider will likely start by asking about your cycle history, any recent changes (new medications, stress, weight shifts), and associated symptoms. The initial workup usually includes blood tests to check your hormone levels, thyroid function, and blood count to assess for anemia. A transvaginal ultrasound gives a clear picture of the uterus, revealing fibroids, polyps, or an unusually thickened lining. In some cases, especially for people over 35 or those with risk factors, a small sample of the uterine lining may be taken to rule out abnormal cell changes.
Treatment depends entirely on the cause. A hormonal imbalance might be managed with progesterone to regulate cycles. Fibroids or polyps can often be removed in a minimally invasive procedure. Thyroid issues respond to medication. The important thing is that a two-week period is a symptom with identifiable causes, not something you should wait out cycle after cycle hoping it resolves.