A period that stretches beyond seven days usually signals that something is disrupting the normal process by which the uterine lining builds up and sheds cleanly each cycle. The causes range from hormonal imbalances and structural growths inside the uterus to underdiagnosed bleeding disorders and thyroid problems. Most are treatable once identified, and the treatments available today can cut menstrual blood loss dramatically. But the sheer number of possible explanations is why a period that consistently runs long deserves medical attention rather than a wait-and-see approach.
What Counts as a Prolonged Period
Clinically, menstrual bleeding that lasts more than seven days is considered prolonged. That threshold comes from international guidelines used by gynecologists to define heavy menstrual bleeding, or what older textbooks call menorrhagia. A Brazilian population study using those same criteria found that about 8% of women of reproductive age reported menstrual flow lasting longer than eight days, while the average across the group was roughly five and a half days.1PLoS ONE. Prevalence of abnormal uterine bleeding in Brazilian women: Association between self-perception and objective parameters So if your period regularly pushes past a week, you are in a meaningful minority, and it is worth figuring out why.
One tricky thing about self-assessment is that many people have trouble distinguishing the tail end of a period from spotting. A day or two of light brown spotting at the very end of an otherwise normal five-day period is not the same thing as seven straight days of red flow. Your clinician will likely ask you to describe the heaviest days, how many pads or tampons you soak through, and whether you pass clots. These details help separate a genuinely prolonged period from one that just tapers slowly.
Hormonal Imbalances and Anovulatory Cycles
The most common reason for prolonged bleeding in otherwise healthy women is a cycle in which ovulation never happens. Without ovulation, the ovary does not produce progesterone, the hormone responsible for stabilizing the uterine lining and triggering a clean, time-limited shed. Instead, estrogen continues to stimulate the lining, which thickens unevenly and eventually breaks down in a piecemeal, drawn-out fashion. Researchers describe this as estrogen breakthrough bleeding: follicles develop enough to produce estrogen at a roughly constant rate but never reach the stage of releasing an egg, so the endometrium grows, becomes unstable, and sheds in irregular waves.2Human Reproduction Update. Types of ovarian activity in women and their significance: the continuum (a reinterpretation of early findings)
Anovulatory cycles are especially common at the two bookends of reproductive life. Teenagers whose hormonal axis has not yet matured often experience them, as do women approaching menopause. Polycystic ovary syndrome (PCOS) is another well-known driver. In PCOS, elevated androgens and insulin resistance interfere with follicle maturation, leading to chronically long or irregular cycles and, when bleeding does occur, episodes that can drag on for weeks.
Structural Growths Inside the Uterus
Three types of benign growths commonly cause prolonged or heavy periods: fibroids, polyps, and adenomyosis. Each disrupts normal bleeding through slightly different mechanisms, and they can coexist.
Fibroids (leiomyomas) are noncancerous muscle tumors of the uterine wall. Those that grow into or distort the uterine cavity tend to cause the heaviest bleeding. Research points to abnormal blood vessel architecture within and around fibroids as a likely explanation. Vessels in fibroids form irregular networks and can create venous pools that bleed more freely when the lining sheds.3PubMed Central. Uterine Fibroids (Leiomyomata) and Heavy Menstrual Bleeding Fibroids are extremely common, affecting the majority of women by middle age, but only a subset produce symptoms severe enough to need treatment.
Endometrial polyps are small finger-like overgrowths of the uterine lining. They contain glands and blood vessels and can act as sources of abnormally heavy or prolonged menstrual bleeding.4PubMed Central. Endometrial polyps: Pathogenesis, sequelae and treatment Because polyps are often small, they may not cause pain, making prolonged bleeding the only clue they exist.
Adenomyosis occurs when tissue similar to the uterine lining embeds itself within the muscular wall of the uterus. It has long been linked to heavy and prolonged periods, painful cramping, and an enlarged, boggy-feeling uterus. That said, a recent review noted that the evidence connecting adenomyosis specifically to abnormal bleeding is muddier than many clinicians assume, partly because adenomyosis frequently coexists with fibroids or polyps and because many cases produce no symptoms at all.5PubMed Central. Adenomyosis and Abnormal Uterine Bleeding: Review of the Evidence In practice, adenomyosis is still treated as a likely contributor when imaging confirms it and other causes have been ruled out.
Bleeding Disorders That Often Go Undiagnosed
If your periods have been heavy and long since your very first cycle, a bleeding disorder is a possibility that deserves investigation. Von Willebrand disease (VWD) is the most common inherited bleeding disorder and a recognized cause of heavy menstrual bleeding, particularly in younger patients.6PubMed Central. von Willebrand disease and heavy menstrual bleeding: when and how to test VWD involves a deficiency or dysfunction in a protein that helps blood clot. The frustrating part is that diagnosis is often delayed by a decade or more, during which time the person may develop iron deficiency, fatigue, and depression from years of excessive blood loss.7PubMed Central. Gynecologic and obstetric management of girls and women with von Willebrand disease
Other clotting factor deficiencies and platelet disorders can produce similar symptoms. If you also bruise easily, bleed excessively after dental work, or have a family history of bleeding problems, bring those details to your doctor. A set of basic blood tests can screen for the most common culprits.
Thyroid Dysfunction and Other Endocrine Causes
Your thyroid gland has a surprisingly strong influence on your menstrual cycle. Hypothyroidism, where the thyroid is underactive, has been associated with heavier and more prolonged menstrual bleeding. One study at a tertiary care center found a significant link between reduced free thyroid hormone levels and menorrhagia.8PubMed Central. Hypothyroidism and Its Impact on Menstrual Irregularities in Reproductive-Age Women: A Comprehensive Analysis at a Tertiary Care Center Interestingly, both an overactive and an underactive thyroid can disrupt cycle regularity, though in slightly different ways. Menstrual disturbances such as missed or infrequent periods have been documented in both conditions.9Endocrine Connections. Endometriosis, polycystic ovary syndrome, and the thyroid: a review
A broader review of endocrine disorders and menstruation found that infrequent periods (oligomenorrhea) are the single most common menstrual complaint across thyroid disease, PCOS, Cushing’s syndrome, and diabetes.10PubMed Central. The Menstrual Disturbances in Endocrine Disorders: A Narrative Review But the flip side of infrequent cycles is that when bleeding does come, the long buildup of endometrial lining can make it heavier and longer than normal. This is why a simple thyroid panel is often one of the first blood tests ordered when someone presents with prolonged periods.
Chronic Infection of the Uterine Lining
Chronic endometritis is a low-grade, persistent inflammation of the endometrium caused by bacteria. Unlike acute pelvic inflammatory disease, it rarely causes fever or sharp pain, so it tends to fly under the radar. A prospective study of women with unexplained abnormal uterine bleeding found chronic endometritis in roughly 70% of them, a strikingly high prevalence. Among those who were successfully treated with antibiotics, bleeding days and heaviness dropped significantly, while women whose infection persisted saw no improvement.11PubMed. High prevalence of chronic endometritis in women with nonstructural abnormal uterine bleeding and benefits of antimicrobial treatment on blood loss pattern A history of pelvic inflammatory disease raises the likelihood of developing chronic endometritis roughly 1.7-fold.12PubMed Central. Analysis of the risk factors of chronic endometritis in infertile women
Chronic endometritis is diagnosed by endometrial biopsy, not imaging. If your prolonged bleeding has no clear hormonal or structural explanation, this is a cause worth discussing with your provider, especially if you also have unexplained infertility.
Copper IUDs and Emergency Contraception
Copper intrauterine devices are highly effective contraception, but heavier, longer periods are one of their best-known side effects. Bleeding irregularities with a copper IUD, including prolonged menstrual bleeding and intermenstrual spotting, are one of the leading reasons women have them removed.13PubMed. Treatment of bleeding irregularities in women with copper-containing IUDs: a systematic review The bleeding tends to be worst in the first few months and often improves over time, but for some users it never fully settles.
Emergency contraception with levonorgestrel (the morning-after pill) can also temporarily alter your next period. One study of over 200 women found that taking emergency contraception changed cycle length, period length, and the appearance of menstrual bleeding, with the effects depending on when in the cycle the pill was taken. Most of these changes disappeared by the following cycle.14PubMed Central. Menstrual bleeding patterns following levonorgestrel emergency contraception So if your period ran unusually long right after taking Plan B, that is a recognized short-term effect rather than a sign of a new underlying problem.
Anticoagulant medications (blood thinners), certain antidepressants, and some herbal supplements with blood-thinning properties can also lengthen or intensify menstrual bleeding. If you have recently started a new medication and your periods have changed, the timing may not be coincidental.
The Perimenopause Effect
If you are in your 40s and your periods are getting longer and heavier, perimenopause is a leading suspect. The years leading up to menopause are marked by fluctuating and often declining progesterone alongside erratic estrogen, which produces many of the same anovulatory-type bleeding patterns seen in teenagers but with a thicker baseline endometrium. Classic research on menstrual blood loss volume documented that women aged 50 bled about 6 mL more per period than women aged 20 to 45, and that heavy bleeding was most common in the approach to the final menstrual period.15PubMed Central. Menstruation and the Menopause Transition
Prolonged episodes are even more telling. Data from the menopausal transition show that 77% of women reported at least three episodes of bleeding lasting ten or more days during this phase of life.16PubMed Central. Management of the Perimenopause While most of this is hormonal and benign, prolonged bleeding in the perimenopausal window still warrants evaluation because fibroids, polyps, and endometrial hyperplasia are also more common at this age.
When to Worry About Endometrial Hyperplasia or Cancer
Prolonged or abnormal uterine bleeding is the most common presenting symptom of endometrial cancer and its precursor, endometrial hyperplasia. That does not mean prolonged bleeding is likely to be cancer. A cross-sectional study of perimenopausal women with abnormal bleeding found endometrial hyperplasia in about 7.5% and cancer in just 1.2%.17PubMed Central. Endometrial Thickness Measurement as Predictor of Endometrial Hyperplasia and Cancer in Perimenopausal Uterine Bleeding: Cross-Sectional Study Still, those numbers are high enough to justify investigation, especially for women over 40 or those with risk factors like obesity, diabetes, or a long history of anovulatory cycles.
Research comparing perimenopausal and postmenopausal women with endometrial cancer found that perimenopausal women tended to have a longer duration of abnormal bleeding before diagnosis.18PubMed Central. Analysis of Characteristics of Endometrial Carcinoma in Peri- and Postmenopausal Women with Abnormal Uterine Bleeding This likely reflects the fact that perimenopausal women are used to irregular periods and may dismiss prolonged bleeding as “just menopause.” If your bleeding pattern has changed substantially and persists, an ultrasound and possibly an endometrial biopsy can provide reassurance or catch a problem early.
Pregnancy-Related Bleeding
A period that seems unusually long or oddly timed can sometimes turn out to not be a period at all. Early pregnancy bleeding, especially from ectopic pregnancy or miscarriage, can mimic an extended period. A case report highlighted a woman who presented with what she described as abnormal menstruation, without any missed period, and was found to have a tubal ectopic pregnancy.19PubMed Central. A Case Of Tubal Ectopic Pregnancy The takeaway is straightforward: if there is any chance you could be pregnant, a pregnancy test should be the first step before attributing prolonged bleeding to anything else.
Iron Deficiency and Fatigue
Prolonged periods are not just inconvenient; they drain your iron stores. Heavy menstrual bleeding is the leading cause of iron deficiency among women of reproductive age.20PubMed. Heavy menstrual bleeding, iron deficiency, and iron deficiency anemia: Framing the issue Iron deficiency does not have to progress all the way to anemia to cause symptoms. Even without frank anemia, low iron can produce fatigue, brain fog, restless legs, hair thinning, and exercise intolerance. The relationship can become a vicious cycle: heavy bleeding depletes iron, and iron deficiency itself may impair the body’s ability to regulate clotting, potentially worsening bleeding further.21PubMed. The relationship between heavy menstrual bleeding, iron deficiency, and iron deficiency anemia
If your periods are lasting more than a week and you feel chronically tired, ask for a ferritin test. Hemoglobin can look normal even when iron stores are nearly empty. Treating the iron deficiency alongside the bleeding itself is key, since replenishing stores while the tap is still running achieves little.
Medical Treatments
Treatment depends on the cause, but several options work across multiple scenarios.
The levonorgestrel-releasing intrauterine system (hormonal IUD) is widely considered the most effective medical treatment for heavy and prolonged periods. In one study, the median blood loss dropped by more than 90% within three treatment cycles, and about 82% of participants met the criteria for treatment success regardless of body weight or whether they had previously given birth.22PubMed Central. Heavy Menstrual Bleeding Treatment With a Levonorgestrel 52-mg Intrauterine Device The hormonal IUD works by delivering a small amount of progestin directly to the uterine lining, thinning it over time. Head-to-head data suggest it reduces blood loss more than combined oral contraceptives, oral progestogens, tranexamic acid, or anti-inflammatory drugs.23PubMed. The levonorgestrel-releasing intrauterine system in heavy menstrual bleeding: a benefit-risk review
Tranexamic acid is a non-hormonal option taken only during the days of heavy bleeding. It works by slowing the breakdown of blood clots in the uterine lining. Studies have documented reductions in menstrual blood loss of roughly 26% to 60%, making it more effective than anti-inflammatory painkillers or placebo.24PubMed Central. Tranexamic acid for the treatment of heavy menstrual bleeding: efficacy and safety It is a good fit for people who prefer not to use hormones or who only need treatment for a few days per month.
NSAIDs such as ibuprofen and mefenamic acid also reduce menstrual bleeding, though less effectively than tranexamic acid or a hormonal IUD. A Cochrane review confirmed that NSAIDs were better than placebo for heavy menstrual bleeding but ranked below both tranexamic acid and the levonorgestrel IUD.25PubMed Central. Non-steroidal anti-inflammatory drugs for heavy menstrual bleeding Their dual benefit of reducing bleeding and easing cramps makes them a practical first-line option for milder cases. NSAIDs have also shown benefit specifically for women whose heavy bleeding is related to a copper IUD.13PubMed. Treatment of bleeding irregularities in women with copper-containing IUDs: a systematic review
Surgical and Procedural Options
When medications are not enough, or when a structural problem like fibroids or polyps is identified, procedures come into play. Hysteroscopic polypectomy (removing polyps through the cervix with a small camera) is straightforward and usually done as a day procedure. Myomectomy removes fibroids while preserving the uterus and is the standard choice for people who want to retain fertility.
Endometrial ablation destroys the uterine lining using heat, radiofrequency energy, or freezing. Patient satisfaction rates after ablation range from 90% to 95%, though complete cessation of periods happens in a smaller fraction, roughly 15% to 60% depending on the technique.26Menopause. Alternatives to hysterectomy Ablation is only appropriate for people who are done having children, because it makes future pregnancies unsafe.
Uterine artery embolization (UAE) is a minimally invasive radiology procedure that cuts off blood supply to fibroids, causing them to shrink. It offers a shorter hospital stay and faster recovery than surgery, but up to about 20% of women need a second procedure within five years.27PubMed Central. Reintervention Rates After Myomectomy, Endometrial Ablation, and Uterine Artery Embolization for Patients with Uterine Fibroids Hysterectomy, the removal of the uterus, remains the only definitive cure for uterine bleeding and is typically reserved for severe cases or when other treatments have failed.
Stress, Weight, and Lifestyle Factors
The brain-ovary connection is real and sensitive. Functional hypothalamic amenorrhea, where the brain essentially dials down reproductive hormones in response to low body weight, excessive exercise, or chronic stress, is well documented in young women.28PubMed. Menses Requires Energy: A Review of How Disordered Eating, Excessive Exercise, and High Stress Lead to Menstrual Irregularities While this more often causes missed periods than prolonged ones, the recovery phase after a period of suppression can produce erratic and extended bleeding as the hormonal axis reboots. The same is true after rapid weight changes in either direction: the body adjusts its hormone output, and the uterine lining does not always cooperate smoothly during the transition.
Obesity also plays a role from the opposite direction. Fat tissue produces estrogen, and in women who carry significant excess weight, that extra estrogen stimulates the endometrium in much the same way an anovulatory cycle does. The result can be thick, unstable lining that sheds irregularly and for longer than normal. Weight management, when relevant, is part of the long-term treatment picture for these patients, not as a substitute for medical treatment but as a way to address the underlying hormonal imbalance.