A normal period lasts between 2 and 7 days. Most people fall somewhere in the middle of that range, but anything within it is considered healthy. Once bleeding extends past 7 days, it crosses into what doctors classify as prolonged or heavy menstrual bleeding, and it’s worth finding out why.
What Counts as a Normal Period
A typical menstrual cycle repeats every 21 to 35 days, and the bleeding portion of that cycle lasts 2 to 7 days. Flow is usually heaviest in the first two or three days, then tapers off. Some people consistently have 3-day periods while others reliably bleed for 6 or 7 days, and both patterns are perfectly normal as long as they’re stable for you.
The key isn’t hitting an exact number of days. It’s whether your pattern stays roughly consistent from cycle to cycle. A period that suddenly lasts several days longer than usual, or one that stretches past a full week, signals that something has shifted.
When Bleeding Goes Past 7 Days
Bleeding that lasts more than 7 days meets the clinical definition of heavy menstrual bleeding. Other signs that your period has crossed into abnormal territory include soaking through a pad or tampon every hour for several hours in a row, needing to double up on pads, waking up at night to change protection, or passing blood clots the size of a quarter or larger. You don’t need to check every box. Any one of these is enough to warrant a conversation with a healthcare provider.
Hormonal Causes of Longer Periods
Hormones orchestrate the entire menstrual cycle, so when they’re out of balance, bleeding patterns change. Polycystic ovary syndrome (PCOS) is one of the most common culprits. It disrupts ovulation, which can lead to irregular, prolonged, or unusually heavy periods because the uterine lining builds up longer than it should before shedding.
Thyroid problems also play a role. An underactive thyroid (hypothyroidism) is strongly linked to heavy, prolonged bleeding. In one study of women with abnormal uterine bleeding, overt hypothyroidism was present in about 15.5% of those with heavy periods, with another 4.5% having a milder, subclinical form. An overactive thyroid tends to push in the opposite direction, making periods lighter or causing them to disappear entirely.
Structural Problems in the Uterus
Sometimes the issue isn’t hormonal but physical. Uterine fibroids, which are noncancerous growths in the muscle wall of the uterus, are extremely common and can make periods both heavier and longer. They distort the uterine lining, increasing the surface area that bleeds each month.
Uterine polyps work differently but produce a similar result. These are overgrowths of the endometrial tissue that lines the inside of the uterus, fueled in part by estrogen. A polyp attaches to the uterine wall by a thin stalk or broad base and can cause bleeding between periods as well as longer, heavier periods. Both fibroids and polyps are treatable, which is one reason identifying the cause of prolonged bleeding matters.
How Perimenopause Changes Your Period
If you’re in your 40s and your periods are suddenly unpredictable, perimenopause is a likely explanation. The transition to menopause begins on average 6 to 8 years before your final period, and it reshapes bleeding patterns significantly. Early in the transition, short cycles under 21 days are common. Later, cycles stretch out, sometimes to 90 days or more between periods.
What catches many people off guard is that periods during this phase don’t just become irregular. They also tend to get heavier and last longer. Bleeding episodes of 10 or more days become more frequent, and the amount of flow becomes much less predictable from month to month. Women in late perimenopause are actually the most likely of any age group to experience excessive blood loss during their periods. About 15 to 25% of women sail through this transition with minimal changes, but the majority notice real disruption.
How IUDs Affect Bleeding Duration
The type of IUD you have makes a big difference. Copper IUDs are well known for making periods heavier and longer, especially in the first few months after insertion. The good news is that this effect decreases over time. Research tracking new copper IUD users found that bleeding dropped by roughly 23% between the first month and the six-month mark. Cramping also improved significantly over that same window.
Hormonal IUDs generally work in the opposite direction. They thin the uterine lining, which typically makes periods lighter and shorter over time. Many people using a hormonal IUD eventually stop getting a period altogether. If you recently switched IUD types and your bleeding pattern changed dramatically, the device itself is the most likely explanation.
The Iron Problem
Prolonged periods aren’t just inconvenient. They drain your iron stores. Every extra day of bleeding means more iron lost, and over several cycles this can tip into iron deficiency or full iron-deficiency anemia. The World Health Organization defines anemia in non-pregnant women as a hemoglobin level below 12.0 g/dL, and iron stores are considered depleted when ferritin drops below 15 to 30 micrograms per liter depending on which guideline you follow.
The symptoms are easy to dismiss as general tiredness: fatigue, weakness, brain fog, feeling short of breath during normal activities, brittle nails, and cold hands and feet. If your periods regularly last more than 7 days or are consistently heavy, ask for a blood test that includes both hemoglobin and ferritin. Hemoglobin alone can look normal even when your iron reserves are already running low.
How Prolonged Bleeding Is Treated
Treatment depends entirely on the cause. For heavy bleeding without an obvious structural problem, hormonal options like birth control pills or a hormonal IUD are often the first step because they thin the uterine lining and regulate the cycle. Non-hormonal medications can reduce the volume of blood loss by 26 to 60%, though they typically don’t shorten how many days you bleed.
When fibroids are the source of the problem, a procedure called uterine artery embolization (UAE) is one option that avoids major surgery. It works by cutting off blood flow to the fibroids, causing them to shrink. Up to 92% of people who undergo UAE for fibroids report no uncontrolled vaginal bleeding 12 months later, and nearly 90% experience partial or full symptom relief. Polyps can usually be removed in a straightforward outpatient procedure. Endometrial ablation, which destroys the uterine lining, is another option for people who are done having children and want to significantly reduce or eliminate their periods.
If your periods are lasting longer than they used to, or you’ve been bleeding past 7 days and treating it as your normal, tracking your cycle length and flow for two or three months gives you concrete information to bring to an appointment. Pattern changes are easier to evaluate than a single unusual cycle.