Menstruation, or a period, occurs when the lining of the uterus exits the body through the vagina. The duration of a person’s period can vary.

Generally, however, a period will last around 4–8 days.

This article will discuss the average duration of a typical menstrual period and a few factors that can affect it. It also provides some information on the menstrual cycle more generally.

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A person’s period may last around 4–8 days.

The menstrual cycle refers to several hormonal changes that occur as a female’s body prepares for pregnancy.

A full menstrual cycle begins on the first day of a period and ends the day before the next period.

A typical period lasts for around 4–8 days. However, the full cycle tends to last for 25–30 days.

Cycles that last for fewer than 21 days are called “polymenorrhea.”

The typical menstrual cycle consists of the following stages:

  • Days 1–5: Follicles that contain an egg develop on the ovaries. This is when the bleeding occurs.
  • Days 6–8: Estrogen levels rise, causing the uterine lining to thicken. Day 8 is typically when the bleeding stops.
  • Day 14: Estrogen levels rise, causing the follicle to release the egg. This is called ovulation.
  • Days 15–24: Progesterone levels rise, thickening the lining of the uterus even more.
  • Days 25–28: Estrogen and progesterone levels drop. The unfertilized egg will leave the body, and the cycle will start all over again.

Learn more about the menstrual cycle here.

Some people experience premenstrual syndrome (PMS) near the start of their menstrual cycle.

PMS symptoms typically begin a few days to 2 weeks before the period starts and end when the cycle is over.

Some symptoms of PMS include:

Learn more about the effects of a period here.

Several possible factors can affect the duration of a period. These include:

  • Age: According to the Office on Women’s Health, for a few years after a person’s first period, the cycle may be longer than 38 days. As a person reaches middle age, however, they may start to experience irregular periods as menopause approaches.
  • Body weight: According to some research, body weight can affect a person’s menstrual function.
  • Certain medications: Some types of birth control can affect a person’s bleeding pattern.

Certain factors and conditions can cause a period to last longer than usual. The sections below describe these factors in more detail.

Intrauterine devices

Some people may experience irregular bleeding or spotting for a few months after getting a nonhormonal or hormonal intrauterine device (IUD).

Bleeding should return to normal, decrease, or stop altogether once the body adjusts to the new IUD.


A person might wish to contact their doctor if they continue to experience heavy menstrual bleeding several months after getting an IUD.

This may happen if an IUD punctures the uterine wall, or if the person develops a bacterial infection in the uterus.

A doctor can check for signs of physical damage and the possible presence of infections.


A doctor may recommend using a different IUD or a different form of birth control if someone experiences heavy menstrual bleeding.

If an IUD punctures the uterine wall, a doctor will remove the IUD, and they may recommend surgery.


Perimenopause, which causes hormone levels to fluctuate, occurs when the body begins transitioning to menopause. People reach menopause roughly 1 year after their last period.

Perimenopause can cause anovulation, which occurs when the ovaries do not release an egg.

The presence of a mature egg stimulates the production of progesterone, which helps regulate menstrual periods. However, a lack of progesterone can lead to heavy bleeding.


No single test can determine whether or not a person has entered perimenopause.

A doctor can confirm perimenopause by reviewing the person’s medical history and current symptoms.

Some doctors may order blood tests to check a person’s hormone levels and rule out other medical conditions that could be causing longer periods.


Perimenopause occurs naturally as the female body transitions into menopause.

A doctor may recommend certain treatments that can help ease a person’s symptoms. For example, hormonal birth control can help alleviate hot flashes and irregular periods.

Getting regular exercise, eating a balanced diet, and getting enough sleep every night can also help make the transition easier for some people.

Pelvic inflammatory disease

Pelvic inflammatory disease (PID) refers to an infection of the female reproductive organs.

People can get PID from:

  • untreated sexually transmitted infections
  • IUDs
  • using feminine hygiene products, such as douches

PID can cause:

  • heavy bleeding
  • spotting or bleeding between periods
  • unusual vaginal discharge
  • lower abdominal pain
  • fever


A doctor can diagnose PID by reviewing the person’s medical history, performing a pelvic exam, and analyzing any vaginal discharge.


Doctors can treat PID using antibiotics.

The symptoms may resolve shortly after starting antibiotic treatment. However, even if this is the case, people should always complete the course of antibiotics.

This ensures that the infection is cured and helps prevent reinfection.


Endometriosis is a medical condition that occurs when the tissue that lines the uterus grows outside of the uterus. Commonly affected areas include the ovaries and fallopian tubes.

This condition can make periods last longer than usual. It can also cause intense menstrual cramps and back pain.


A doctor can diagnose endometriosis by performing a laparoscopy. During this procedure, they will use a camera — inserted into the pelvis through a small incision near the belly button — to examine the pelvic organs.

Specifically, they will look for cysts, scarring, or abnormal tissue deposits behind the uterus.

Doctors can also use ultrasound scans to find endometriosis cysts that they may have missed during a pelvic exam.


Currently, no cure exists for endometriosis. Treatments tend to focus on alleviating pain and addressing fertility concerns.

Treatments for endometriosis vary depending on a person’s age, their health status, and the severity of their condition.

Some treatment options for endometriosis include:

  • over-the-counter or prescription pain medication
  • hormone therapy
  • surgical removal of any cysts

The following sections will discuss some factors and conditions that may cause a period to be shorter than usual.

Hormonal birth control

Hormonal birth control contains hormones, including estrogen and progestin, that can either thicken the mucus lining the cervix or prevent ovulation.

People who start a new type of hormonal birth control may experience irregular periods.

However, they may notice that their periods become lighter over time. People with an IUD may stop having periods altogether.


When a person starts a new form of hormonal birth control, a doctor will discuss the possible side effects and what to expect.

A person can speak with their doctor about any new or worsening symptoms they experience while using the hormonal birth control.

A doctor may perform a physical exam or run blood tests to rule out any possible underlying medical conditions.


A doctor can recommend an alternative type of birth control that may help address the symptoms.

For instance, if a person has an IUD but prefers having regular periods, the doctor may recommend switching to hormonal birth control pills instead.

Polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is a common health condition that affects up to 5 million people in the United States, according to the Centers for Disease Control and Prevention (CDC).

PCOS occurs when fluid filled sacs develop on the ovaries. The exact cause remains unknown, but people with PCOS tend to have high levels of insulin and male hormones called androgens.

Androgens can prevent ovulation, which can cause irregular periods.

People with PCOS may have fewer periods than usual, or they may miss periods altogether.

Some other symptoms of PCOS include:

  • excess hair on the face and body
  • acne
  • hair loss
  • unexpected weight gain


Doctors can diagnose PCOS using blood tests.

They use these tests to check a person’s hormone levels. People who have high levels of androgens may have PCOS.

They may also perform a pelvic exam or ultrasound to check for signs of endometriosis.


Treatments for PCOS primarily focus on symptom relief and management.

Hormonal birth control and medicines that block androgens can help reduce acne and regulate menstrual cycles.

Reaching a moderate body weight and eating a balanced diet may help regulate insulin levels.

A person should contact their doctor if they notice any significant changes in their menstrual cycle.

Some other reasons to see a doctor include:

  • severe abdominal cramps
  • bleeding that lasts for longer than 8 days
  • bleeding or spotting between periods
  • unusual vaginal discharge
  • fever

Periods typically occur once every 28 days, and the bleeding lasts around 4–8 days.

Many factors can affect the duration of a person’s period. These include:

  • age
  • hormone levels
  • body weight
  • diet
  • medications

A person should contact a doctor if they notice any significant changes in the frequency or duration of their periods.